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1、Basic Electric Charges: The discovery of the electron as the first subatomic particle is credited to J.J. Thomson Robert Millikan (Millikan Oil Drop Experiment): Measure the charge on an electron using the apparatus. Ernest Rutherford (Rutherfords Experiment): Perform a gold foil experiment that had
2、 tremendous implications for atomic structure. Alpha Particles Mass Number, Isotopes, and Atomic Weight Atomic number: the smallest particle of an element; number of protons in nucleus; identity of element Protons and neutrons each have mass of roughly 1 atomic mass unit (amu). Electrons have practi
3、cally no mass. Mass number = protons + neutrons Isotopes: Two atoms of the same element differ in the number of neutrons (mass number) in their nuclei. Average of the mass numbers (does not appear on the periodic table) is called the atomic weight. Sublevels and electron configuration: The configura
4、tion that corresponds to the lowest electronic energy is called the ground state. Any other configuration is an excited state. Example: the ground state configuration of the sodium atom is 1s22s22p63s, the first excited state is obtained by promoting a 3s electron to the 3p orbital, to obtain the 1s
5、22s22p63p configuration. Periodic Table Properties: Acid-forming properties increase from left to right. The atomic radii of elements decrease from left to right across a period Metallic properties are greatest on the left side. First ionization energies increase from left to right across a period.
6、Electronegativity increase from left to right across a period. (Highest F 4.0) Empirical Formula & molecular formula An empirical formula shows the ratio of atoms within a molecule. Molecular formula of hydrogen peroxide is H2O2. The empirical formula for hydrogen peroxide is HO. Quantum Theory Bohr
7、 model: the incorrect idea that electrons orbit the nucleus in true orbits Heisenberg principle: electrons are located in orbitals, not orbits One cannot know an electrons position and momentum at the same time De Broglies hypothesis: matter (including electrons) can be thought of as having properti
8、es of both a particle and a wave Intramolecular Force Strong Ionic Bonds: Electronegativity values of two kinds of atoms differ by 1.7 or more. Nonpolar Covalent Bonds: Electronegativity difference between two atoms is 0 or very small (not greater than 0.5) Polar Covalent Bonds: Electronegativity va
9、lues of two kinds of atoms differ by 0.4 to 1.6. Intermolecular Forces Weak Dipole-Dipole Attraction: Found in polar-molecules, unsymmetrical distribution of electronic charges. London Dispersion Forces: Found in both polar and nonpolar molecules, the weakest of all the electrical forces. Hydrogen b
10、onds: Attractive force between the lone pair of an electronegative atom and a hydrogen atom that is bonded to nitrogen, oxygen, or fluorine. Hydrogen bonds occur between, not within molecules. Resonance The contributing structures are not isomers. They differ only in the position of electrons. Each
11、Lewis formula must have the same number of valence electrons (and thus the same total charge), and the same number of unpaired electrons, if any. VSPER Theory Molecule Type Shape Electron Arrangement Geometry Examples AX1En Diatomic HF, O2 AX2E0 Linear BeCl2, HgCl2, CO2 AX2E1 Bent NO2, SO2, O3, CCl2
12、 AX2E2 Bent H2O, OF2 AX2E3 Linear XeF2, I3, XeCl2 AX3E0 Trigonal planar BF3, CO32, NO3, SO3 AX3E1 Trigonal pyramidal NH3, PCl3 AX3E2 T-shaped ClF3, BrF3 AX4E0 Tetrahedral CH4, PO43, SO42, ClO4, TiCl4, XeO4 AX4E1 Seesaw SF4 AX4E2 Square planar XeF4 AX5E0 Trigonal bipyramidal PCl5 AX5E1 Square pyramid
13、al ClF5, BrF5, XeOF4 AX5E2 Pentagonal planar XeF5- AX6E0 Octahedral SF6, WCl6 AX6E1 Pentagonal pyramidal XeOF5, IOF52 AX7E0 Pentagonal bipyramidal IF7 AX8E0 Square antiprismatic ZrF84-, ReF8- AX8E1 Square antiprismatic XeF82- AX9E0 Capped square antiprismatic ReH92 Hybridization AX1 (e.g., LiH): no
14、hybridisation; trivially linear shape AX2 (e.g., BeCl2): sp hybridisation; linear or digonal shape; bond angles are cos1(1) = 180 AX3 (e.g., BCl3): sp2 hybridisation; trigonal planar shape; bond angles are cos1(1/2) = 120 AX2E (e.g., GeF2): bent / V shape, More Stability Lower Entropy + Higher Energ
15、y - Less Stability Exothermic reaction - energy is released - H enthalpy decreases Endothermic reaction - energy is absorbed - H enthalpy increases Hf = Hf (products) - Hf (reactants) If G 0, then the reaction is spontaneous in the reverse direction. Laws of Thermodynamics The zeroth law of thermody
16、namics: states that if two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other. The first law of thermodynamics: states the energy of an isolated system is constant. The second law of thermodynamics: the principle of the increase of entropy and explains the phenomenon of irreversibility in na
