Physical Science Notes PDF - Origin of Elements

PHYSICAL SCIENCE Theone Yamila A Quimno | 11 Our Lady of Czestochowa | SEM 2 Topic 1: The Origin of Element ​ The universe is composed of Comparison of human and star -73% hydrogen​ lifetime: -25% helium​...

PHYSICAL SCIENCE Theone Yamila A Quimno | 11 Our Lady of Czestochowa | SEM 2 Topic 1: The Origin of Element ​ The universe is composed of Comparison of human and star -73% hydrogen​ lifetime: -25% helium​ Protostar = fetus -2% others Fusion ignition-main sequence = The Big Bang Theory is the accepted baby-adult scientific theory about the universe's origin. Red giant/supergiant = middle age “Big Bang“ was a phenomenally energetic White dwarf = old age-death explosion that initiated the universe's expansion. All matter and energy were compressed into singularity at the time of ​ Supernova Nucleosynthesis the explosion. The age of the universe is -formed the elements heavier than Fe. calculated at 13.7 billion years.​ -Elements heavier than iron are made primarily when giant stars explode in ​ First 3 minutes of big bang: supernova events.​ -Nuclear reaction began to form elements -stars will take seven million years to fuse through the collision of protons and hydrogen and helium. This is why heavier neutrons, these can fuse to form isotopes elements like gold, mercury, and platinum of hydrogen. Isotopes are different are very expensive. “versions” of an element.​ -the universe was hot enough for a nuclear reaction to continue and form the third isotope of hydrogen, tritium = of the first, Topic 2: The Atomic Concept namely hydrogen, helium, and lithium. Greek Philosophers and their beliefs ​ Empedocles (450 B.C.) ​ Nucleosynthesis -He conceptualized that all matter is made - Formed the light elements (H, He, and of earth, water, air, and fire. He is also Li) by combining the simple nuclei or credited with the idea that “Nothing comes atomic particles by nuclear reaction with from nothing,” giving us hints at the laws extremely hot temp and pressure. of conservation of energy and mass. ​ Stellar nucleosynthesis ​ Leucippus & Democritus - Formed the elements heavier than Be to - Proposed that matter is made up of Fe as the universe cools, protons and invisible particles or atoms. Atoms are neutrons can fuse and form heavier nuclei. indivisible or uncuttable, thus regarded as -All hydrogen and most helium in the the basic building block of nature and the universe 100 seconds after the explosion, entire universe. He named the smallest and a small amount of lithium was made. piece of matter “atoms,” meaning “not to -Stars end the nuclear reactions of the be cut.” element iron due to its stability and the lack of a neutron source. PHYSICAL SCIENCE Theone Yamila A Quimno | 11 Our Lady of Czestochowa | SEM 2 ​ Plato (360 B.C) -He coined the word “element.” An atom has three parts: -earth as hexahedron/cube, water as Proton = positive icosahedrons, air as octahedron, and fire as Neutron = no charge tetrahedron. The heavenly element or ether Electron = negative is a dodecahedron. The proton & neutron are found in the center of the atom, a place called the ​ Aristotle (350 B.C) nucleus. The electrons orbit the nucleus. -He modified an earlier theory that matter was made of four “elements” ​ JJ Thomson – earth, fire, water, and air. Aristotle was -In 1904, Thompson developed the idea wrong. However, his theory persisted for that an atom was made up of electrons 2000 years. ​ scattered unevenly within an elastic sphere -Plato and Aristotle proposed that matter surrounded by a soup of positive charge to was continuous and always present all balance the electron's charge. around us. - Proposed a model called the plum pudding model. He was awarded a Nobel Alchemist’s Contribution to Chemistry ​ Prize in 1906 for discovering the electron. -They identified several metal elements ​ Ernest Rutherford like mercury, iron, and gold, which led to -Atom nearly all space Center of the atom the understanding that there were many has a densely positively charged region = more than just four elements Nucleus -They are the first to investigate how ​ Henry Mosely materials could be changed into other -He experimented using X-rays to study substances. the sequence of chemical elements in ​ John Delton Mendeleev's periodic table. This led to the -In 1808, Dalton proposed a modern atomic development of the concept of the atomic model based on experimentation and not number, which is the number of protons in on pure reason. the nucleus. -All matter is made of atoms. -He demonstrated that elements must be - Atoms of an element are identical. arranged based on their atomic number. -Atoms of different elements are ​ Neils Bohr distinctively different -Improved the planetary model that -Atoms are rearranged in chemical electrons can be excited and move to higher reactions energy levels for a certain period when -Atoms of different elements combine in energy is added. His model is also known as constant ratios to form compounds. the Rutherford-Bohr planetary model. -Atoms of one element cannot be changed ​ Erwin Schrodinger into atoms of different elements. -Developed Bohr atom model, this new model is known as the quantum mechanical model of the atom. PHYSICAL SCIENCE Theone Yamila A Quimno | 11 Our Lady of Czestochowa | SEM 2 ​ Nuclear Reactions and the 3.​ Ionic Covalent Bond Synthesis of New Elements - (ΔEN)>1.7 ​ Polar V.S Nonpolar “molecules” Alpha emission α or 𝟐/𝟒𝐇ⅇ Polar Molecules - Molecules are not Beta emission Β, β- , or 0/-1 ⅇ equal on all sides. A polar molecule has bonds that do not cancel out, and One part Positron β+ or 𝟎/1ⅇ of the molecule is more negative than the emission other part of the molecule, Hydrophilic(water-loving) Nonpolar Molecules- Is equal on all Topic 3: The Particulate Nature of sides. Has all nonpolar (or one-polar) Matter bonds that cancel out. Geometrically Electronegativity (EN) - measures the symmetrical enough to allow cancellation of relative tendency of an atom to attract the polar bonds. Hydrophobic electrons to itself when chemically (water-fearing) combined with another atom. We could use the electronegativity values of the atoms ​ Dipole Moments involved to get the absolute -Is a measure of the polarity of a bond. It is electronegativity difference (ΔEN), which represented by a special arrow. It points will help us in predicting what type of toward more EN atoms. chemical bond (ionic, polar covalent, or ​ Intermolecular Forces nonpolar covalent) would exist between INTERmolecular forces - alternative forces them. You do the larger electronegative between neighboring molecules. value minus the smaller one, which would INTRAmolecular forces - hold atoms give you your difference. together in a molecule. ​ 3 Classifications of Covalent ​ Intermolecular Forces affect “bond” chemical properties. 1.​ Polar Covalent Bond Boiling point, melting point, viscosity, and -unequal sharing (or a partial transfer) of surface tension increase as the strength of electrons. intermolecular forces increases. However, - e- density is drawn toward a side, an atom vapor pressure and volatility decrease with acquires a partial negative charge, While increasing strength of IMFA. the other atom acquires a partial positive charge. - (ΔEN) 0.5- 1.7 Intermolecular forces: 2.​ Nonpolar Covalent Bond ​ Ion- Dipole -They almost have the same Ion- Dipole forces are attractive forces electronegativity values between an ion and a polar molecule. -highest e-density occurs between atoms. ​ Dipole-dipole - (ΔEN)