Chapter 3-4 Chemistry Notes PDF

Chapter 3: Matter and its Properties  Chapter 3 Subtopics: a. Pure Substances b. Mixtures c. States of Matter d. Changes in Matter e. Properties of Matter Lesson Objectives: Explain what matter is; At the end of Distinguish mixtures from pure substances b...

Chapter 3: Matter and its Properties  Chapter 3 Subtopics: a. Pure Substances b. Mixtures c. States of Matter d. Changes in Matter e. Properties of Matter Lesson Objectives: Explain what matter is; At the end of Distinguish mixtures from pure substances based on a set of the properties; chapter, Discuss the different states of matter; students should be Identify the key features of physical and chemical changes.; and able to: Recognize the difference between physical and chemical, and intensive and extensive, properties.  Matter is anything that What is matter? occupies space and has mass. Pure Substances Are substances that have definite and constant composition. Have a fixed set of properties.  Pure Substances Element Compounds A pure substance A pure substance consisting of only one kind consisting of two or more of atom in the form of kinds of atoms in the form homoatomic molecules or of heteroatomic molecules individual atoms. or individual atoms.  Classifying Substances When sulfur, an element, is heated in air, it combines with oxygen to form sulfur dioxide. Classify sulfur dioxide as an element or a compound. Because sulfur and oxygen are both elements and they combine to form sulfur dioxide, the molecules of sulfur dioxide must contain atoms of both sulfur and oxygen. Thus, sulfur dioxide is a compound because its molecules are heteroatomic  Mixtures A mixture is a combination of two substances or elements. Have varying physical and chemical properties.  Mixtures Homogeneous Heterogeneous Has uniform composition Mixtures in which the properties throughout. and appearance are not uniform throughout the sample. All substances exist in one Substances can exist in different state of matter. states of matter at once. Identify the following as homogeneous or heterogeneous mixtures. 1. Saltwater 2. Coffee 3. Opened soda drinks 4. Gravel and sand 5. Salad States of Matter  STATES OF MATTER SOLID LIQUID GAS It has a definite Has definite Has no fixed shape and volume but no volume or shape. volume. definite shape. Particles vibrate Particles are Particles are more tightly packed freely at high loosely packed together. than in a solid. speed.  STATES OF MATTER PLASMA Has no fixed volume or shape. Are electrically conductive, produce magnetic fields and electric currents, and respond strongly to electromagnetic forces. Lightning, electric sparks, fluorescent lights, neon lights, plasma televisions, some types of flame and the stars are all examples of illuminated matter in the plasma state.  STATES OF MATTER Bose-Einstein Condensate A state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero. BECs have been used to create atom lasers, atomic clocks and gravitational, rotational or magnetic sensors with excellent sensitivity. Changes in Matter  Physical Changes Changes in Matter Chemical changes Physical Changes Are those in which It’s the shape, size, or reversible. state of the matter changes, but the substance is still essentially the same.  Phase Changes It is the transformation of matter from one phase to another. It always involves absorption or release of heat.  Changes in States of Matter Exothermic Reaction Endothermic Reaction A process that releases heat, A process that absorbs heat causing the temperature of the and cools the surroundings. immediate surroundings to rise. Melting Condensation Freezing Evaporation Deposition Sublimation Recombination Ionization Chemical Changes Occur when the composition of a substance is changed, which requires the breaking and forming of chemical bonds during a chemical reaction. Result in the production of a new substance, thus, it’s irreversible. Properties of Matter  Physical Properties Properties of Matter Chemical Properties  Physical Properties Are properties that can be measured or observed without changing the chemical nature of the substance. Intensive Property Extensive Property  Physical Properties Intensive Property Extensive Property - Any characteristic of - Any characteristic of matter that does not matter that depends on depend on the amount the amount of matter of the substance present. being measured. Some examples of physical properties are: - color (intensive) - density (intensive) - volume (extensive) - mass (extensive) - boiling point (intensive) - melting point (intensive)  Chemical Properties As any of a material’s properties that becomes evident during a chemical reaction, that is, any quality that can be established only by changing a substance’s chemical identity.  CHAPTER 4: STRUCTURE OF MATTER  CHAPTER 4: SUBTOPICS a. Early Ideas About Matter d.Isotopes b. Development of the Atomic Theory e. Structure of the Atom c. Inside the Atom f. Arrangement of Electrons in the Fundamental Particles Atom Atomic Number, Atomic Mass, g. Energy Sublevels Mass Number Number of Neutron in the Nucleus h. Electronic Configuration  LESSON OBJECTIVES: At the end of the chapter, students should be able to: A. Describe an atom; B. Trace the development of atomic theory; C. Discuss the different fundamental particles of an atom; D. Differentiate among atomic number, mass number, and isotopes, and which of these distinguishes one element from another; and E. Describe how electrons are grouped within atoms; EARLY IDEAS ABOUT MATTER LET’S WATCH THIS! Get a pen and paper and be ready for questions. Pause the video for the questions. Video from: https://youtu.be/LCzLTQABYdE?t=366  EARLY IDEAS ABOUT MATTER Democritus (460-370BC) All matter was composed of small, finite particles that they called “atomos”, a term derived from the Greek word for “indivisible.” He thought of atoms as moving particles that differed in shape and size, and which could join together. He proposed that different types and combinations of these particles were responsible for the various forms of matter.  EARLY IDEAS ABOUT MATTER Aristotle (322 BC) He proposed that all things are made up of the four elements fire, water, air, and earth. He believed all materials on earth were made up of small amounts of each element.  EARLY IDEAS ABOUT MATTER John Dalton (1803) He revised the ideas of Democritus. He proposed the “Dalton’s Atomic Theory” in 1803. DEVELOPMENT OF THE ATOMIC THEORY Dalton’s Atomic Theory All matter is composed of extremely small particles called atoms. Atoms cannot be subdivided, created, or destroyed. Atoms of a given element are identical in size, mass, and other properties. Atoms of different elements differ in size, mass, and other properties. Atoms of different elements can combine in whole number ratios to form chemical compounds; In chemical reaction, atoms are rearranged, combined, or separated. DEVELOPMENT OF THE ATOMIC THEORY J.J. Thomson An English chemist who lived from 1856-1940. He is credited with the discovery of the electron in the late 1900s, which was the first subatomic particle to be discovered. He proposed the 'Plum-Pudding Model' of the atom. DEVELOPMENT OF THE ATOMIC THEORY PLUM-PUDDING MODEL The electrons were embedded in a uniform sphere of positive charge. DEVELOPMENT OF THE ATOMIC THEORY ERNEST RUTHERFORD A student of J.J. Thomson, who proposed the 'planetary' model of atoms, made up of a positively- charged nucleus surrounded by orbiting electrons. Had discovered the atomic nucleus in 1911 and had observed the proton in 1919. Image from: https://experimentwithperspectives.blogspot.com/2014/02/rutherfords-model-of-atom.html DEVELOPMENT OF THE ATOMIC THEORY RUTHERFORD PLANETARY MODEL Described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the electrons, circulate at some distance, much like planets revolving around the Sun. DEVELOPMENT OF THE ATOMIC THEORY NIELS BOHR He improved on Rutherford’s Planetary Model. Developed the Bohr atomic model in 1913, with electrons travelling in orbits around the nucleus, and chemical properties being determined by how many electrons are in the outer orbits DEVELOPMENT OF THE ATOMIC THEORY BOHR ATOMIC MODEL In an atom, electrons (negatively charged) revolve around the positively charged nucleus in a definite circular path called orbits or shells. Each orbit or shell has a fixed energy and these circular orbits are known as orbital shells. DEVELOPMENT OF THE ATOMIC THEORY JAMES CHADWICK An English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932, elementary particles devoid of any electrical charge. STRUCTURE OF THE ATOM Atoms has the nucleus where the mass of the atom is concentrated at the center. The nucleus consists of protons that are positively charged and neutrons that has no charge. Electrons are negatively charged and orbits the nucleus. FUNDAMENTAL PARTICLES OF ATOM BERZELIUS NOTATION OF AN ELEMENT ✓ The letters designate the chemical symbol for the element. BERZELIUS NOTATION OF AN ELEMENT ✓ The number in the upper portion is the element’s atomic number. BERZELIUS NOTATION OF AN ELEMENT ✓The number at the lower portion is its mass number.  BERZELIUS NOTATION OF AN ELEMENT In representing elements using this notation, it is easy to remember that mass numbers are always greater than atomic numbers. Hence, your chemical representation is correct if the left superscript (A) is greater than the left subscript (Z). BERZELIUS NOTATION OF AN ELEMENT Zinc (Zn), for example, has an atomic number of 30 and an atomic mass of 65.38 amu. In some cases, only the mass number is shown. This notation is also read as zinc-65, or Zn-65.  THE ATOMIC NUMBER The atomic number (Z), In a neutral atom, the also referred to in most number of protons is equal references as the proton to the number of electrons. number (p), represents the Therefore, the atomic total number of protons number also shows the present in an element. number of electrons in a neutral atom.  The Mass Number The number of neutrons in an atom can also be calculated by taking the difference between the mass number and the atomic number.  Examples: Number of Number of Number of Atomic Mass Element protons (p) electrons (e) neutrons (n) number (Z) number (A) helium 2 2 2 2 4 lithium 3 3 4 3 7 beryllium 4 4 5 4 9 boron 5 5 6 5 11 carbon 6 6 6 6 12  The Charge Number ✓ When electrons are removed in an atom, it becomes charged and is transformed to an ion. ✓ Since electrons are negatively charged, the removal of electrons produces positively charged ions called cations. ✓ Atoms that gain electrons from external sources become negatively charged ions called anions.  The Charge Number The charge number (q) is determined as the difference between the number of protons and the number of electrons.  The Charge Number The general notation for any neutral element, where X is its chemical symbol, A is its mass number, and Z is its atomic number.  The Charge Number ❑ When does the charge number become positive? -If a neutral atom loses electrons, then it become positively charged. ❑ When does the charge number become negative? -If a neutral atom gains electrons, then it will become negatively charged.  Let’s Practice! 1. Given the chemical symbol of Br, determine its number of protons, electrons, and neutrons. 33  Let’s Practice! 2. Given the chemical symbol of manganese (V) ion, determine its number of protons, electrons, and neutrons. SEATWORK #1: Instruction: Arrange the following substances in increasing order depending on the property provided. 1.proton number: Zn, Al, In 2.electron number: Pt2+, P𝑏4+, Ir 3.neutron number: Mn5+, Fe2+, Co3+  ISOTOPES Are atoms that have the same atomic number (protons & electrons), but different mass numbers (neutrons). Some elements, such as carbon, potassium, and uranium, have multiple naturally-occurring isotopes. Isotopes are defined first by their element and then by the sum of the protons and neutrons present.  Carbon-12 contains six protons, six neutrons, and six electrons; therefore, it has a mass number of 12 amu (six protons and six neutrons). Carbon-14 contains six protons, eight neutrons, and six electrons; its atomic mass is 14 amu (six protons and eight neutrons). PRACTICE!! How many neutrons are in each isotope of oxygen? Write the symbol of each isotope. a. Oxygen-16 b. Oxygen-17 c. Oxygen-18 ARRANGEMENT OF ELECTRONS IN THE ATOMS  ARRANGEMENT OF ELECTRONS Electrons in atoms can have only certain specific energies. Electrons are organized according to their energies into sets called shells. Generally, the higher the energy of a shell, the farther it is (on average) from the nucleus. ARRANGEMENT OF ELECTRONS Shells are further divided The subshells of each shell are into subsets of electrons labeled, in order, with the letters called subshells. The first s, p, d, and f. Thus, the first shell shell has only one subshell, has only a single s subshell the second shell has two (called 1s), the second shell has subshells, the third shell has 2s and 2p subshells, the third shell has 3s, 3p, and 3d and so forth. three subshells, and so on. ARRANGEMENT OF ELECTRONS Shells Number of Subshells Maximum Names of Subshells No. of Subshells Electrons 1 1 s 2 1s 2 2 p 6 2s, 2p 3 3 d 10 3s, 3p, 3d 4 4 f 14 4s, 4p, 4d  ELECTRON CONFIGURATION Are shorthand descriptions of the arrangements of electrons in atoms. The order in which electrons are placed into the orbitals is based on the order of their energy. This is referred to as the Aufbau principle. The electrons fill lower-energy atomic orbitals before filling higher-energy ones (Aufbau is German for "building-up"). Shortcut way: Use the previous noble gas to abbreviate the configuration. You just have to finish the configuration from where the noble gas leaves PRACTICE!! What is the electron What is the electron configuration of a configuration of a neutral phosphorus neutral chlorine atom? atom?