Classifications of Matter PDF

SH1690 CLASSIFICATIONS OF MATTER 1. Mixture – substance with varying compositions 2. Pure Substance – substance with unifor m a. Heterogeneous mixture – a mixture in which composition the components can still be identified a. Element – a substance composing of Examples...

SH1690 CLASSIFICATIONS OF MATTER 1. Mixture – substance with varying compositions 2. Pure Substance – substance with unifor m a. Heterogeneous mixture – a mixture in which composition the components can still be identified a. Element – a substance composing of Examples: only one kind of atom 1. Garden Salad Example: 2. Trail mix of nuts 1. Ds (Darmstadtium) b. Colloid – a mixture with observed properties 2. H (Hydrogen) as homogeneous mixtures, but b. Compound – a substance composing heterogeneous when subjected to tests of molecules, a combination of atoms Examples: which are made up of 2 or more 1. Milk elements 2. Styling gel Examples: c. Homogeneous mixture (Solution) – a mixture 1. Aqua Fortis (HNCO 3 ) with a very uniform composition 2. Water (H2 O) Examples: 1. Brine (saltwater) 2. Orange juice drink PHASES OF MATTER Solid is the state of matter with a defined appearance. It has its own shape, and has very little to no molecular movement. This is the state of matter with a very rigid molecular structure. An example is diamond. Liquid is the state of matter with molecular movement. Its movement is dictated by how fast the liquid flows. It has no shape of its own due to its loose molecular structure. Instead, it takes the shape of its container. An example is a glass of lemon juice. Gas is the state of matter with high molecular movement. Its molecular structure is looser than liquid. It behaves the same way as a liquid. An example is the air we breathe. 01 Handout 1 *Property of STI Page 1 of 3  SH1690 Plasma is the state of matter with a very high molecular movement. Due to heat, a gas becomes plasma due to the energy it absorbs and releases, making its molecules move even faster. High temperature plasmas glow a certain color. An example is the neon light fixture seen in restaurants. PHASE TRANSITIONS in matter happens when heat is introduced. Heat allows molecules to absorb energy, thereby increasing its energy levels. Increasing energy means movement among particles. Removing heat causes the molecules to lose energy, compacting together. Figure 1. Phase Transition of Matter 1. Melting – process of adding heat to a solid, causing its form to become a liquid Scraps of iron (Fe) bars melted to be reformed into solid iron blocks 2. Evaporation – process of adding heat to a liquid, causing its loose molecular bonds to break further, turning into a gas Saltwater (NaCl (aq)) is made to evaporate in a saltwater flat to extract salt Δ (NaCl (aq) NaCl + H2O ↑) 3. Ionization – process of adding heat to a gas, adding energy to it, charging the molecules into ions (plasma is made up of ions) Energy is added in a glass tube filled with Neon (Ne), making the Neon gas to glow due to the ionization process 4. Recombination – process of removing heat in a plasma, returning the ions to a ground state, becoming a gas. Sometimes called deionization. Neon plasma deionizes back to its gaseous form once it begins to cool 5. Condensation – process of transferring energy in gas molecules to the surrounding area, forcing the gas molecules to form bonds and coalesce into a liquid Water vapor condenses back to liquid water to form clouds 6. Freezing – process of transferring heat in liquids to the surrounding area, forcing the molecules to reform and bond into a solid Liquid Mercury (Hg), poured into a mold, is solidified when poured with liquid nitrogen (N 2 (aq)) 7. Sublimation – process of adding energy to a solid, dissipating into a gas without transitioning to the liquid phase 01 Handout 1 *Property of STI Page 2 of 3  SH1690 Frozen Carbon dioxide (CO 2 ) sublimates into carbon dioxide gas (CO2 ↑) when exposed to room temperature 8. Deposition – process of transferring energy from the gas molecules to the surrounding area, forcing them to combine and make “deposits” of clumped gas molecules together, reforming into a solid Water vapor (H 2 O ↑) deposits itself as ice crystals (H2 O) when forming snowflakes PROPERTIES OF MATTER Physical Property is the property of matter in which the material can be quantified using measurements. It is also the property in which the material can also be assessed by the five senses. o Examples are mass, color, length Chemical Property is the property in which the material is assessed from its chemica l structure, processes, and results. o Examples are flammability, toxicity, enthalpy (total heat content in a system) Extensive Property is the property in which the material is dependent on its physical properties. If any physical property changes in a material, its extensive properties change accordingly. o Examples are mass, area, length Intensive Property is the property in which the material is independent on its physical properties. o Examples are color, temperature, density CONSUMER PRODUCTS Food Additives are substances added to food and/or beverages to improve flavor and appearance. They are also used to preserve the natural taste of food. Active Ingredients are substances that are biologically active. They are used mostly in pharmaceutical drugs and commodities like soap, powders, and others. Cleaning Agents are substances that are used to remove dirt, along with dust, stains, clutter, and foul odor. They may also kill some harmful microorganisms in the cleaning process. Cosmetics are substances that enhance the consumer’s appearance. Cosmetics also improve the consumer’s fragrance. References: Ahmad, W., Beckman, K., Vong, P., & Zheng, J. (2015, September 14). Classifications of matter. Retrieved from LibreTexts: Chemistry: http://chem.libretexts.org/Core/Analytical_Chemistry/Qualitative_Analysis/Classification_of_Matter Brown, T. L., LeMay, H. E. Jr., Bursten, B. E., & Burdge, J. R., (2004), Chemistry: The central science (9th ed.), Upper Saddle River, New Jersey, Pearson Education, Inc. Leach, M. R. (1999 - 2016). The chemical classification of matter. Retrieved from The Chemogenesis Web Book: http://www.meta-synthesis.com/webbook/31_matter/matter.html Russell, B. (1995). History of western philosophy. Routledge. Santiago, K.S., & Silverio, A. A. (2016). Exploring life through science: Physical science. Quezon City: Phoenix Publishing House Strathern, P. (2000). Mendeleyev's dream – the quest for the elements. New York: Berkley Books. 01 Handout 1 *Property of STI Page 3 of 3  SH1690 CLASSIFICATIONS OF CLEANING AGENTS Surfactants, or surface-active ingredients, are chemical agents that aid in cleaning surfaces that contain oil, stains, and dirt, which usually are not soluble in water. They include a hydrophilic (water- loving) polar head and a hydrophobic (water-fearing) nonpolar tail. The head interacts with polar molecules like water, while the tail that is usually comprised of a hydrocarbon chain attaches to nonpolar substances like oil. Bleaching agents are formulations that cause whitening – or lightening – to an affected substrate by solubilizing color-producing substances or by altering their light-absorbing properties. These substances are usually oxidizing agents, such as peroxides and chlorine. Disinfectants are substances made to lessen, if not eradicate, harmful microbes on surfaces. Sanitizers work in the same manner as disinfectants. Types of Cleaning Agents: 1. General-purpose cleaners are substances that are weakly alkaline intended for a variety of uses. Compounds found in these cleaners are generally alcohols, silicates, sodium carbonate, phosphates, and sodium EDTA. 2. Bathroom cleaners are products specifically designed for bathroom surfaces, such as tubs, tiles, and toilet bowls, which generally develop stains like mildew. They are either acidic or alkaline, depending on the surface they will be used on. Alkaline cleaners are best to use for bathroom floors, walls, tiles, and bathtubs because they preserve the enamel finishes of these surfaces; acidic cleansers can damage enamels. Cleansers with acidic active ingredients like phosphoric acid and citric acid are recommended for other bathroom parts with rust and mineral deposits. Some cleansers have additional components, such as surfactants, that aid in the removal of soap and fatty deposits. Furthermore, toilet bowl cleaners are usually liquid and acidic and may contain bleaching agents such as hydrogen peroxide or hypochlorite. 3. Special surface cleaners are substances designed to clean certain surface materials such as glass, vinyl, carpets, and upholstery, to name a few. Glass cleaners typically contain water, glycol ethers, ammonia, and alcohols. They are commercially available as moistened towelettes or liquid or aerosol sprays. Carpet and upholstery cleaners are sold as liquid shampoos or as powders. Both forms may contain surfactants, foam stabilizers, alcohols, and/or glycol ethers, but the powders may have additional porous carrier materials that trap dirt. One advantage of powders over liquids is that they allow for more natural cleaning of the surface with vacuum cleaners. 4. Stain and deposit removers are substances designed to remove spots, usually with the aid of abrasive materials such as steel wools and brushes. They are typically commercialized in fluids and stick forms, but they can also be sold in powder and paste forms. These substances contain crystalline and amorphous silica, feldspar, clay, and chalk alongside surfactants, solvents, and enzymes. They are sometimes improved by adding ingredients such as sodium carbonate, bleaching agents, and oxalic acid. CLASSIFICATIONS OF COSMETICS 1. Lotions are substances that generally moisturize and soften the skin. They usually contain mineral oil, beeswax, preservatives, and perfumes or fragrances. Lotions that contain a high amount of hydrating ingredients are specifically called moisturizers. They contain emollients that decrease skin flaking by creating a layer of oil on top of the skin. This layer traps water and prevents it from escaping the skin, thus keeping the skin hydrated. 2. Deodorants are products designed to prevent and remove unpleasant body smells and are available in the market as liquids, powders, or sprays. They contain aluminum or zirconium compounds as active ingredients. 3. Perfumes are products that impart a fragrant odor and are usually composed of aromatic oils, alcohol, and water. 4. Shaving creams soften hair strands in many different parts of the body, which allows for their easy removal. They are mainly made up of stearic acid, mineral oils, water, perfume, and preservatives. 5. Toothpaste, which cleanse and polish teeth and freshen breath, contain polishing agents, surfactants, sweetener, and flavoring agents. 6. Shampoos are used to cleanse hair, with their main ingredients include surfactants and antidandruff substances. Other components include colors, perfumes, and preservatives. 01 Handout 2 *Property of STI Page 1 of 2  SH1690 7. Skin whiteners, which are among the most popular products nowadays, contain bleaching or antioxidant substances like glutathione, Metathione, hydroquinone, tretinoin, and kojic acid that inhibit melanin production in the skin. Reference: Santiago, K.S., & Silverio, A. A. (2016). Exploring life through science: Physical science. Phoenix Publishing House 01 Handout 2 *Property of STI Page 2 of 2  SH1690 The Origin of Elements Big Bang theory is the most dominant and highly supported theory of the origin of the universe. This theory states that the universe began in an explosion from an initial point or singularity which has expanded over billions of years to form the universe as we now know it. I. Big Bang Nucleosynthesis The is a process believed to have taken place in the early moments of the universe, shortly after the initial expansion took place according to the Big Bang theory. This process, origina lly proposed formally in 1939 by George Gamow and Ralph Alpher, is consistent with the known astronomical observations and is widely accepted by the scientific community. It explains the creation of light elements in the intense heat of the early moments following the Big Bang through a process of nuclear fusion. The process did not contain enough heat to create heavier elements, which were formed through different nucleosynthesis methods. Nuclear Fusion - a nuclear reaction in which two light nuclei (such as hydrogen) combine to form a heavier nucleus (such as helium). The process releases excess binding energy from the reaction, based upon the binding energies of the atoms involved in the process. According to the theory, the density of the early universe shortly after the Big Bang generated enough heat to trigger a process of nuclear fusion that combined single protons (the simplest form of the hydrogen atom) together creating lighter elements: helium , lithium , and beryllium. It also merged them with neutrons , allowing for isotopes such as deuterium , which is a variation of hydrogen that contains a proton and a neutron in its atomic nucleus. Because the early universe was the same everywhere, this process seems to have taken place pretty much uniformly throughout the universe, which explains why everywhere we look, the major distribution of elements is roughly the same. The total process lasted about 17 minutes, beginning about 3 minutes into the period of space expansion. About 20 minutes after the universe began to expand, the universe had cooled to the extent that this fusion process was no longer taking place. II. Stellar Nucleosynthesis: How Heavy Elements are formed in Stars This is the process by which elements are created within stars by combining the protons and neutrons together from the nuclei of lighter elements. A. The history of how the theory evolved: The first to suggest that nuclear fusion reactions were taking place in the stars was Arthur Eddington in 1920. The conversion of hydrogen to helium was the stellar source of energy. George Gamow later on developed a formula to calculate the probability of such reactions taking place (Gamow Factor). Hans Bethe in 1939, proposed two processes used to convert hydrogen to helium. The first, proton-proton cycle, is taking place in stars with similar mass to our Sun. The second, CNO cycle (carbon-nitrogen-oxygen cycle), is taking place in much more massive stars. Later, in 1946, Fred Hoyle suggested that even heavier nuclei are forming in stars, such as carbon and iron. Many corrections on Hoyle's theory followed and A. G. W. Cameron and D. D. Clayton discovered and explained the further stages of nucleosynthesis. 02 Handout 1 *Property of STI Page 1 of 4  SH1690 B. Other Types of Nucleosynthesis: Apart from the case of fusion reactions during the lifetime of a star, scientists have discovered that the formation of heavy elements takes place in other cases as well: Explosive or Supernova Nucleosynthesis - The process that takes place during the explosion of a star. Elements such as silicon and nickel are formed through fast fusion. Cosmic Ray Spallation - The impact of fast protons or cosmic rays against the interstellar medium results in the spallation phenomenon. During this process, the heavier nuclei of carbon or oxygen fragment into lighter elements such as Be, B, and Li, making these elements more abundant compared to the ratios that result by other types of nucleosynthesis. C. Reaction Cycles during the Synthesis of Heavy Elements in Stars: Source: www.wikipedia.org Hydrogen Burning: This first stage begins with the proton- proton cycle, otherwise known as the proton-proton chain (see diagram at left), where hydrogen is converted to helium. This process dominates in stars that have a similar mass to the Sun. When the energy is sufficient to overcome the electrostatic or Coulomb repulsion (electrostatic force of repulsion exerted by one charged particle on another charged particle of the same sign) forces among the protons, the fusion takes place. This process is made by stars less than or equal to one (1) solar mass (one solar mass equals to the mass of our Sun). As seen in the diagram, fusing two (2) hydrogen atoms yield a neutron-containing deuterium (and isotope of hydrogen), a positron, and a neutrino. Subsequent fusion with hydrogen yields Helium 3 (an 02 Handout 1 *Property of STI Page 2 of 4  SH1690 isotope of Helium) and a gamma ray in the form of a photon. Fusing two (2) 3 He gives two 1 H and 4 He. Other forms of hydrogen fusion exist, but this time it is done by stars with solar masses greater than one solar mass. These hydrogen proton- proton chain processes allow for the fusion of heavier elements in rapid succession. This leads to higher energy fusion; expending hydrogen faster than it could replenish. One process involves fusing Beryllium- 7 (7 Be) in order to create carbon (see image at right). Another proton-proton process Source: www.wikipedia.org involves in the fusion of Boron-8 (8 B). Boron is the element that is one step away to being carbon. High-energy hydrogen fusion processes tend to forego the helium burning process (see below) because these massive stars have fused 4 He already in the high- energy process, allowing them to fuse heavier elements together. Still another method of high-ener gy Source: www.wikipedia.org hydrogen fusion occurs in massive stars. Source: www.wikipedia.org It is the carbon-nitrogen-oxygen (CNO) cycle (see right), in which the three elements are used as catalysts in order to fuse four protons and produce an alpha particle, two neutrinos and two positrons. After a cycle of reactions, the result is the formation of a helium nucleus. This is a cyclical process that tend to regulate the CNO atoms made in the process to fuel the star. This makes 02 Handout 1 *Property of STI Page 3 of 4  SH1690 the method a slow and deliberate process, allowing stars who use this fusion method to live longer lives than those who fuse heavier elements rapidly. Helium Burning: The second stage Source: www.wikipedia.org begins after most of the hydrogen is burned, which is around this time a main sequence star (which our Sun belongs to) turns into a Red Giant. Helium burning (see image at right) is done either through the alpha process or the triple-alp ha process. In the triple-alpha process, two helium-4 (4 He) nuclei or alpha particles fuse to form 8 Be (Beryllium-8). Fusing it with another alpha particle yields a carbon nucleus. As soon as carbon is present, the alpha process begins where the formation of neon, oxygen and silicon takes place. Burning of Heavier Elements: If the star is massive enough, another set of nuclear fusion reactions begins. These include the burning of carbon, neon, oxygen and silicon that lead to the formation of heavier elements and finally iron. Production of Heavier Elements than Iron: After the production of iron, the star collapses under its own gravity due to a lack of fusion, because Iron absorbs energy rather than release it. Thus, the star bursts into a supernova, where it can either turn into a neutron star or a black hole. A neutron star is made if the star is more massive than the Sun, but not as much as a black hole. A black hole is formed if a really massive star collapses in its own gravity, pulling anything in its center. Here, other processes take place including the neutron capture where heavier isotopes (nuclei with more neutrons) are produced, and the proton capture where heavier element nuclei are produced. References: Berndt, Chang, R. and Goldsby, K. (2013). Chemistry (11th edition). New York, NY: McGraw- Hill Companies, Inc Fraser, C. (2015). Size of stars. Retrieved November 22, 2016 from Universe Today: http://www.universetoday.com/25331/size-of-stars/ The Big Bang Theory. Retrieved October 13, 2014 from: http://physics.about.com/od/astronomy/f/BigBang.htm The Big Bang Nucleosynthesis. Retrieved October 13, 2014 from: http://physics.about.com/od/physicsatod/g/BigBangNucleosynthesis.htm Nuclear Fusion. Retrieved October 13, 2014 from: http://physics.about.com/od/glossary/g/nuclearfusion.htm How Elements are formed in Stars. Retrieved October 20, 2014 from: http://www.brighthub.com/science/space/articles/108157.aspx 02 Handout 1 *Property of STI Page 4 of 4  SH1690 PROTOSTARS AND THEIR LIVES Protostar 𝛂 Some nebulae never initiate their protostar development because they are impeded by another more massive star, such as the case of the planet Jupiter. It has been theorized that Jupiter is a failed star because its solid hydrogen core was impeded by the Sun’s heavier mass, preventing Jupiter from collecting more hydrogen gas to initiate its fusion. However, if Jupiter were able to get more hydrogen gas in space, it would become an alpha protostar, which would become a Brown dwarf, a star whose mass lies between least massive stars and the densest gas giant planets. Since they cannot fuse hydrogen into other elements, it is theorized that brown dwarfs combine hydrogen to form deuterium instead; thus, their light never reaches the visible spectrum. Protostar 𝛃 If the nebula has enough mass to form an actual star, it becomes a beta protostar, which then becomes a Main Sequence star, such as our Sun. Main-sequence stars live out its life longer and slower, allowing for more element formation until it becomes a red giant. Red giant stars now use the helium it has made during its life as a main-sequence star to form heavier elements, such as iron. Once the red giant collapses because it cannot utilize the heavier elements for fusion, its outer layers collapse and become a planetary nebula, a star that has been mistaken by astronomers in the past as planets because their light is constantly radiating, never flickering in the night sky. Once the planetary nebula loses its shine, it becomes a white dwarf – the remaining core of the main sequence star. It does not create new elements because it tries to preserve itself using the materials in itself until its last light fades. Protostar 𝛄 We have the gamma protostar, the stars that live fast and die young. Because they are formed from an extremely massive nebula, the protostar is formed from the collapsing matter due to gravity. Once it has enabled fusion, it will draw in more hydrogen as it quickly fuses them to create other elements. Because of its intense gravity, it uses up its hydrogen and expands into a supergiant. These heavyweights may appear blue or red, depending on their rate of fusing heavier elements. Because they were combining too much heavier elements, these supergiants tend to collapse onto itself, releasing its contents as a bright supernova. Now, depending on its mass before its “death,” there are two forms it can assume. If its weight is less than or equal to 1.3 solar masses, it becomes a neutron star, whose core is made primarily of neutrons. However, exceeding the 1.3 solar mass limit turns the supergiant into a black hole, a celestial object so dense and heavy, its gravity is strong enough to trap light in it. ELEMENT FORMATION IN HIGH-DENSITY STARS Basic Hydrogen Chain Some stars start with the standard proton-proton chain. However, upon (“proton-proton”) creating a helion nucleus, they immediately fuse it with the helium they just made, releasing more energy and creating beryllium. But this beryllium is unstable, so it releases energy to stabilize itself into lithium. This lithium nucleus is then fused with another hydrogen, forming the helium that shall be used to form beryllium once more. Advanced Hydrogen Some stars take it to the next level: by fusing the already-unstable beryllium Chain with hydrogen to form boron, releasing even more energy. This boron, however, is so unstable it releases a positron (the electron’s opposite twin) as well as energy in an attempt to stabilize itself into beryllium. But this new beryllium is more unstable than the previous one. Thus, this new beryllium splits itself into two helium nuclei to achieve stability. REFERENCE: Santiago, K.S., & Silverio, A. A. (2016). Exploring life through science: Physical science (1st ed). Phoenix Publishing House. 02 Handout 2 *Property of STI Page 1 of 1  SH1690 The Atom, its Structure, and its Development The People behind the Atomic Theory Leucippus  Stated to be Democritus’ mentor (around 500 - 401  He theorized that motion is meaningless without the Void, and BC) it is wrong to associate the Void with nonexistence.  His definition of the Void is actually a vacuum.  He theorized as well that everything that is real contain indivisible parts that comprise it, making these indivis ib le things also real.  Democritus borrowed his mentor’s idea, and improved upon it. Empedocles  Proposed that everything is made up of four (4) elements: (490 – 430 BC) Fire – the element that can “cut” and “move”, but it is “light”. It is both “hot” and “dry”. Air – the element that can “move” and is “light”, but cannot “cut”. It is both “hot” and “moist”. Water – the element that cannot “cut” and is “heavy”, but can “move”. It is “cold” and “moist”. Earth – the element that cannot “cut” and “move”, and “heavy” as well. It is “cold” and “dry”. Democritus  Proposed that if you kept cutting a substance in half forever, (460 - 370 BC) eventually you would end up with an “uncuttable” particle.  He called the particles atoms, meaning “indivisible” in Greek.  Democritus thought that atoms were small, hard particles of a single material and in different shapes and sizes.  He thought that atoms were always moving and formed different material by combining with each other.  Aristotle disagreed with Democritus’ idea that would end up with an indivisible particle. Because Aristotle had greater public influence, Democritus’ ideas were ignored for centuries. Plato  Proposed that everything made is not meant to be changed. (428 - 348 BC)  Improved the idea of the four classical elements (fire, air, water, and earth) by adding specific corpuscles (tiny particles), in which every form of matter can be divided into one of the basic four geometric solids, each having a unique shape. Tetrahedron for fire because its penetrating points and sharp edges made it mobile. Octahedron for air because it can penetrate, but is less mobile than fire. Icosahedron for water because it cannot penetrate anything and is less mobile. 03 Handout 1 *Property of STI Page 1 of 4  SH1690 Cube for earth because it is immobile and stable.  Due to the theory that each form of matter can be divided by means of mathematics, and each corpuscle has an unchanging level of reality, it offered a good account of changes among the primary substances. John Dalton  In his time, scientists knew that elements combined with each (1766 - 1844) other in specific proportions form compounds.  Dalton claimed that the reason for this was because elements are made of atoms.  His atomic theory can be summarized below: Elements are composed of extremely small particles called atoms All atoms of a given element are identical, with the same size, mass, and chemical properties. The atoms of one element are different from the atoms of all other elements. Compounds are composed of atoms of more than one element. In any compound, the ratio of the numbers of atoms of any of the two elements present is either an integer or a simple fraction. A chemical reaction involves only in separation, combination, or rearrangement of atoms; it does not result in their creation or destruction. Amedeo Avogadro  Corrected John Dalton’s theory in which equal volumes of gas, (1776 - 1856) at equal temperature pressure contain equal numbers of molecules.  His law allowed him to study and deduce the diatomic nature of numerous gases by studying the volumes at which these gases reacted.  His law is as follows: The amount of molecules, or atoms, in one mole of a material is equal to the Avogadro’s number (NA), which is equal to 6.0221415 × 1023. The relationship of mass and volume of same gases, at same temperature and pressure, corresponds to the relationship between their respective molecular weights. 03 Handout 1 *Property of STI Page 2 of 4  SH1690 Robert Brown  Noticed that dust particles within pollen grains seem to be (1773 - 1858) jiggling erratically when it floats on water, for no reason.  Jan Ingenhousz (1785) also described the movement by using coal dust floating on alcohol.  It was Albert Einstein (1905) and Marian Smoluchowski (1906) proved Brown’s and Ingenhousz’s previous observations. They have observed that the random jiggling motion the dust particles made were, in fact, driven by the movement of smaller particles in the liquid, which came to be known as atoms and molecules. Joseph J. Thomson  Thomson used a cathode-ray tube to conduct an experiment (1856 - 1940) which showed that there are small particles inside atoms.  This discovery identified an error in Dalton’s atomic theory. Atoms can be divided into smaller parts.  Because the beam moved away from the negatively charged plate towards the positively charged plate, Thomson knew that the particles are negatively charged.  He called these particle corpuscles. But now, these particles are called electrons.  Thomson changed the atomic theory to include the presence of electrons. He knew there must be positive charges present to balance the negative charges of the electrons.  He proposed a model of an atom called the “plum-pudd ing” model, in which negative electrons are scattered throughout soft blobs of positively charged material. Ernest Rutherford  Rutherford conducted an experiment in which he shot a beam of (1871 - 1937) positively charged particles into a sheet of gold foil.  He predicted that if atoms were soft, as the plum-pudding model suggested, the particles would pass through the gold and continue in a straight line.  Most of the particles did continue in a straight line. However, some of the particles were deflected to the sides a bit, and few bounced straight back.  Rutherford realized that the plum-pudding model did not explain his observations. He changed the atomic theory and developed a new model of the atom.  He proposed that the nucleus is the tiny, extremely dense, positively charged region in the center of an atom.  Rutherford calculated that the nucleus was 10,000 times smaller than the diameter of the atom.  In Rutherford’s model, the atom is mostly empty space, and the electrons travel in random paths around the nucleus. Niels Bohr  Bohr suggested that electrons travel around the nucleus in (1885 - 1962) definite paths.  These paths are located at certain “levels” from the nucleus.  Electrons cannot travel between paths, but they can jump from one path to another. 03 Handout 1 *Property of STI Page 3 of 4  SH1690 Henry Moseley  Moseley studied under the laboratory of Ernest Rutherford. (1887 - 1915) There, he developed the application of X-ray spectra to study the atomic structure.  By measuring the wavelengths of the x-rays given off by certain metals, he was able to determine the number of positive charges in the nucleus of an atom.  He revalidated the importance of the atomic number. Louis de Broglie  He suggested that the modern atomic theory is based on the (1892 - 1987) wave nature of the atom.  In the wave mechanical theory, any moving particle has associated wave properties, hence in relation to the atom, the nucleus is a single cluster of particles at the center of the atom.  Since electron have wave properties, electrons had no well- defined orbits. Since electrons do not move about an atom in a definite path, like the planets around the sun, electrons instead move about in waves around the nucleus in a specific wavelength. Erwin Schrödinger  Adapted de Broglie’s idea and explored the idea of whether or (1887 - 1961) not the movement of electrons in an atom could be explained better as a wave than as a particle.  Explained that electrons are wave functions. As such, waveforms do not behave in a linear manner. Werner Heisenberg  The father of quantum mechanics. (1901 - 1976)  Proposed that every particle behaves in patterns that, when subjected to changes, may or may not be the same as it was before.  Studied extensively about subatomic particles. Reference: Berndt, Chang, R. and Goldsby, K. (2013). Chemistry (11th edition). New York, NY: McGraw- Hill Companies, Inc Fraser, C. (2015). Size of stars. Retrieved November 22, 2016 from Universe Today: http://www.universetoday.com/25331/size-of-stars/ The Big Bang Theory. Retrieved October 13, 2014 from: http://physics.about.com/od/astronomy/f/BigBang.htm The Big Bang Nucleosynthesis. Retrieved October 13, 2014 from: http://physics.about.com/od/physicsatod/g/BigBangNucleosynthesis.htm Nuclear Fusion. Retrieved October 13, 2014 from: http://physics.about.com/od/glossary/g/nuclearfusion.htm How Elements are formed in Stars. Retrieved October 20, 2014 from: http://www.brighthub.com/science/space/articles/108157.aspx 03 Handout 1 *Property of STI Page 4 of 4  SH1690 Table of Isotopic Masses and Natural Abundances This table lists the mass and percent natural abundance for the stable nuclides. The mass of the longest lived isotope is given for elements without a stable nuclide. Nuclides marked with an asterisk (*) in the abundance column indicate that it is not present in nature or that a meaningful natural abundance cannot be given. The isotopic mass data is from G. Audi, A. H. Wapstra Nucl. Phys A. 1993, 565, 1-65 and G. Audi, A. H. Wapstra Nucl. Phys A. 1995, 595, 409-480. The percent natural abundance data is from the 1997 report of the IUPAC Subcommittee for Isotopic Abundance Measurements by K.J.R. Rosman, P.D.P. Taylor Pure Appl. Chem. 1999, 71, 1593-1607. 03 Handout 2 *Property of STI Page 1 of 6  SH1690 03 Handout 2 *Property of STI Page 2 of 6  SH1690 03 Handout 2 *Property of STI Page 3 of 6  SH1690 03 Handout 2 *Property of STI Page 4 of 6  SH1690 03 Handout 2 *Property of STI Page 5 of 6  SH1690 References Audi, G., & Wapstra, A. H. (1993). The 1993 Atomic Mass Evaluation: (I) Atomic Mass Table. Nuclear Physics A, 1-65. Audi, G., & Wapstra, A. H. (1995). The 1995 Update to the Atomic Mass Evaluation. Nuclear Physics A, 409-480. Bièvre, P. D., Böhlke, J. K., Coplen, T. B., Ding, T., Holden, N. E., Hopple, J. A.,... Xiao, Y. K. (2002). Isotope-abundance variations of selected elements (IUPAC Technical Report). Retrieved December 12, 2016 from IUPAC: https://www.iupac.org/publications/pac/pdf/2002/pdf/7410x1987.pdf Table of Isotopic Masses and Natural Abundances. Retrieved December 12, 2016 from the North Carolina State University: https://www.ncsu.edu/chemistry/msf/pdf/IsotopicMass_NaturalAbundance.pdf 03 Handout 2 *Property of STI Page 6 of 6  SH1690 The Atom, Its Structure, and Its Development Atoms from the Eyes of Philosophers and Scientists The Four Classical According to the fundamental Greek theory of matter, as proposed by the Elements natural philosopher Empedocles (490-430 BC), everything came from the four (4) classical elements -- Fire, Air, Water, and Earth (that which became the basis of every action fantasy genre in fiction). He even asserted that each element is associated with two (2) distinct properties, which, given the proper proportions required to "mix" these elements, create everything. For example, the metal iron is classified as earth and air material because it exists as a cold and dry object but becomes hot and moist when melted. Living creatures (yes, including humans) have the softness and life that only water and fire can provide. You can refer to these properties below. Figure 1. The classical elements and their properties as proposed by Empedocles, named as pyr (fire), aer (air), ydor (water), and ge (earth) The Four Classical Aristotle (384-322 BC) supported Empedocles' idea about the four elements Elements: Now with and even added a fifth one: Aether (sometimes spelled ether or æther). This Aether! idea then prevailed during his time, up until the end of the 17th century! This principle is also used by alchemists in their studies. 03 Handout 3 *Property of STI Page 1 of 8  SH1690 Figure 2. The classical elements of pyr, aer, ydor, and ge was also accompanied by aither (aether) Atomism: The Democritus (460-370 BC) was one (1) of the many Greek philosophers who Movement that was didn't agree with the "Five Elements" theory. He believed that everything is Left Ignored made of very small particles, which can be achieved through numerous divisions of material until the tiniest material couldn't be divided any further. This particle, dubbed atomos (Gk. "undivided"), was stated to be the origin of all things. However, this idea didn't sit well with Aristotle. Because of Aristotle's popularity and assertion over the Five Elements theory (and that all matter is continuous and can be divided infinitely), the Atomism movement was largely ignored, until the 1800s. Alchemy: The Alchemists intertwined their chemical endeavors with spiritual and mystical Precursor to concepts, including the study of the five (fire, air, water, earth, and aether) Chemistry classical Western elements, to transmute base metals such as iron and tin into "pure" metals such as gold and platinum. They also used these to discover universal cures for all diseases and achieve longevity (or immortality). Though these proto-chemists all failed in their quests, their studies paved the way for the discovery of common compounds we now use today, such as soaps, charcoal, and color dyes. Alchemy also contributed to the rise of using systematic, logical approaches to the study, expanded knowledge for medicinal chemistry, and even helped develop industrial chemistry. 03 Handout 3 *Property of STI Page 2 of 8  SH1690 The Birth of The Five Elements theory held its ground for years, until Robert Brown Chemistry published his research in 1661, entitled The Sceptical Chymist (The Skeptical Chemist). This encouraged scientists to conduct experiments and use the results to further develop chemistry. In 1808, John Dalton came up with a theory that marked the beginning of the modern era of chemistry. His postulates, dubbed as Dalton's atomic theory, is summarized as follows: 1. Elements are made up of small indivisible particles called atoms; 2. In any given pure element, all properties of a particular element are uniform throughout its atoms. Atoms of different elements differ in their properties; 3. Compounds are composed of atoms of different elements. The component atoms in a given compound exist only in whole-number ratios (i.e., no fraction or decimal values); 4. Atoms are conserved in chemical reactions -- they are only rearranged, separated, or combined with other atoms. Dalton's concepts about matter and atoms were more detailed than the Atomism movement proposed by Democritus. Though he didn't study the atom itself, he surmised these during his research on water, where the atoms of a certain gas (named hydrogen) combined with another gas (i.e., oxygen) to form water. He stated that both elements have different properties despite both existing in the gaseous states. His [Dalton] third postulate is named the Law of Multiple Proportions, where it illustrates that if two (2) or more different compounds are composed of the same two (2) elements, then the ratio of the masses of the second element combined with the given mass of the first element is always a ratio of small whole numbers (you can refer here for more information). This law supported Joseph Proust's findings of the composition of matter. In 1779, Proust proposed an important principle that quantitatively analyzed chemical reactions. He [Proust] suggested that the formation of compounds involves the combination of elements in similar proportions by mass regardless of the sample size. Dalton's last postulate is now known as the Law of Conservation of Mass because matter is neither created nor destroyed. Since there are other discoveries in between these major game changers in Chemistry, here is the summary of those events. A Timeline on the Brief History on Matter and Atoms Year Significant Event 450 BC Empedocles asserted that all things are composed of four (4) primal elements. 400 BC Democritus formed the Atomism movement. Aristotle supported Empedocles' theory and proposed that matter is continuous and can 380-320 BC be divided infinitely. 1799 Joseph Proust proposed the Law of Definite Proportions. 1808 John Dalton formulated the Atomic theory and proposed the Law of Multiple Proportions. 03 Handout 3 *Property of STI Page 3 of 8  SH1690 Dmitri Mendeleev (can also be Mendeleyev or Mendeleef) rearranged all known chemical 1869 elements in his time in a table based on their atomic masses, essentially creating the very first Periodic Table. Antoine Becquerel and Marie Curie observed that radioactivity causes some atoms to The 1890s break down spontaneously. 1895 Wilhelm Röntgen (or Roentgen) discovered X-rays. 1897 Joseph John "J.J." Thomson discovered electrons. Thomson also proposed the "plum-pudding" atom model, where electrons are dispersed 1904 throughout the atom itself. 1908-1917 Robert Millikan found that an electron has a charge of −1.6022 × 10−19 C (coulombs). 1910-1911 Ernest Rutherford noted that atoms are mostly space. Niels Bohr proposed the "orbital" or "planetary" atom model. 1913 Henry Gwyn Jeffreys Moseley (or Henry Moseley) used x-ray spectra to study atomic structures. 1919 Rutherford discovered protons. 1932 James Chadwick discovered neutrons. The Structure of an Atom An atom is defined as the smallest unit of a chemical element, containing all the properties of that element. It has two (2) basic parts: the nucleus and the electrons. Electrons are tiny particles that move around the nucleus, carrying a negative nuclear charge equal to −1.6022 × 10−19 coulombs. The nucleus is the central part of the atom that carries its atomic mass. It is made of two (2) nucleons: protons and neutrons. Protons are tiny particles 1,836 times heavier than electrons and carry nuclear positive charges equal (yet, opposing) to the charge value of electrons. Neutrons are tiny particles that are slightly heavier than protons and carry zero (0) nuclear charge. Atomic Number and Atomic Mass The discovery of the subatomic particles prompted other scientists to study the variations in the characteristics of elements! English physicist Henry Gwyn Jeffreys Moseley experimentally found that different metals bombarded with electrons emitted x-rays of varying degrees. He attributed these differences to the metals' differing positive charges contained in their nuclei. By correlating the resulting frequencies to certain whole number values, each element gets its atomic number. The atomic number is the number of protons in a chemical element, serving as its identity as written in the Periodic Table. The number of protons and electrons in an atom dictates its charge. Ideally, an element is neutral if both protons and electrons have the same number. If neutrons are added with protons, which are neutrally charged, they form the atom's atomic mass! The atomic mass (sometimes referred to as the mass number) is the number of protons and neutrons combined. It dictates how heavy an atom's nucleus (and the atom itself) is. Normally, all chemical elements 03 Handout 3 *Property of STI Page 4 of 8  SH1690 have neutrons. Hydrogen is the only element without any neutrons. That doesn't mean that it will never have one, though! We can summarize this by referring to the reference image below. Figure 3. How to read a chemical element's symbol and its coefficients Both atomic mass and atomic number are used in arranging elements and identify their properties. Dmitri Mendeleev created the very first Periodic Table, arranging the elements according to their atomic masses. There were some gaps in it, hinting that there were (and still are) elements yet undiscovered. However, Henry Moseley argued that the elements must be arranged through their atomic numbers. This configuration is still being used in modern-day Periodic Tables. Isotopes and Nuclear Decay In most cases, atoms of a certain chemical element have different masses. Previously, we have established that all atoms in a given element have the same properties, including its atomic mass and number! Both statements can't be true, is it? Well, in the study of both Chemistry and Physics, it can be possible through isotopes. Isotope is a term used by chemists and physicists to call a variation of an element. Each isotope has the same atomic number, but they differ in atomic mass. Figure 4. The various isotopes of hydrogens Source: http://terpconnect.umd.edu/~wbreslyn/chemistry/isotopes/isotopes-of-hydrogen.html As an example, hydrogen has three (3) isotopes. Its base isotope is protium, while both deuterium and tritium are its variant isotopes. These isotopes are the ones first made after the events of the Big Bang. But, not all isotopes are named the same way hydrogen's isotopes do. Instead, isotopes of other elements are named in two (2) ways. First, they can be named the same way presented in the previous image. As an example, given are three (3) known isotopes of the chemical element Carbon, its base isotope being the first in the series. 03 Handout 3 *Property of STI Page 5 of 8  SH1690 Figure 5. The various ways the isotopes of carbon existing on Earth The second method of naming isotopes is by writing its name (or elemental symbol) followed by a dash and its associated atomic mass. Using the previous example, we can rewrite them as: 1. Using the elemental symbol a. C-12 b. C-13 c. C-14 2. Using the chemical name a. Carbon-12 b. Carbon-13 c. Carbon-14 Not all isotopes are stable, however. If an element has an unstable isotope, it undergoes a process known as radioactive decay. The process of radioactive decay (also known as nuclear decay) stabilizes an unstable isotope by releasing its excess mass in the form of radiation. Radioactive decay has three (3) types: alpha (α), beta (β), and gamma (γ) decay. Alpha-decay is the process where an unstable chemical element releases a helium nucleus, also known as an Alpha-particle (α), from its unstable nucleus to achieve stability. Doing this converts the unstable chemical element into another element, although its stability may vary. When observed in a cloud chamber, the ejected particle travels in a straight line because of its mass. As an example, the given equation is the alpha decay of Polonium-210. Mathematically, it is written as, , where, X Original Element A Original atomic mass Z Original atomic number Y New element after decay Subsequently, if an α-particle is launched directly to an element, it creates a new one and ejecting a neutron in the process. Mathematically,. As an example, given is the α-bombardment of beryllium-9. 03 Handout 3 *Property of STI Page 6 of 8  SH1690 The method of nuclei bombardment is not limited to helium nuclei. Scientists have also used isolated element nuclei and bombard them to other elements to create new elements. Take the element Darmstadtium (Ds). This heavy metallic element is made by bombarding Pb-208 atoms with isolated nuclei of Ni-62. This gave them,. Beta-decay is the process where an unstable chemical element releases a beta-particle (β) to achieve stability. Doing this does NOT convert the unstable chemical element into another element. The unstable element tries to stabilize itself by converting a neutron inside it into a proton, releasing the excess mass as a β-particle. When observed in a cloud chamber, β-decay particles travel in curved paths. This process is done in three (3) ways. The first version of β-decay is called a "β-Minus" decay because it ejects an electron after achieving stability through β-decay. As an example, given is the β-minus decay of carbon-14. Mathematically,. The second version of β-decay is called a "β-Plus" decay. This one ejects a positron after achieving stability through β-decay. A positron is the antiparticle counterpart to an electron. Antiparticles are the primary study in the field of antimatter. As an example, given is the β-plus decay of oxygen-15. Mathematically,. The third version of β-decay does NOT involve any ejection of particles. This one has the atom absorbing its electron to create a neutron for stability. This form of β-decay is known as the "Electron Capture." This decay is supported by the given notion that an electron's negative charge, combined with a proton's positive charge, creates a neutron, with its excess momentum and energy ejected as an electron neutrino (see the given equation). 𝑝 + 𝑒 → 𝑛 + 𝜈𝑒. As an example, given is the decay of mercury-201. Gamma decay is the process that is always active and in conjunction with the other decay processes. It releases a gamma (γ) particle, a massless particle that has both momentum and energy. The energy γ- particle carries the excess energy resulting from the decay of a radioactive element. Mathematically, 𝑎𝑛𝑦 𝑑𝑒𝑐𝑎𝑦 𝑝𝑟𝑜𝑐𝑒𝑠𝑠 → 𝑟𝑒𝑠𝑢𝑙𝑡𝑖𝑛𝑔 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 + 00𝛾. Using the previous examples, we can rewrite them to have γ-emissions. 03 Handout 3 *Property of STI Page 7 of 8  SH1690 Gamma decay is also known to spontaneously occur onto itself without undergoing any other decay methods. This is done to release more excess energy because of its instability. This is mostly observed in highly radioactive materials such as uranium-238, although it can be done by other materials. As an example, uranium-238 is highly radioactive. Thus, it constantly releases mass and energy to stabilize itself. Reference: Santiago, K.S., & Silverio, A. A. (2016). Exploring life through science: Physical science (1st ed). Phoenix Publishing House. 03 Handout 3 *Property of STI Page 8 of 8