SAT II 化学知识点,公式总汇.pdf

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 (Rutherford’s Experiment): Perform a gold foil experiment that had 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 practically 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 configuration that corresponds to the lowest electronic energy is called the ground state. Any other configuration is an excited state. 2 2 6 Example: the ground state configuration of the sodium atom is 1s 2s 2p 3s, the first excited state is obtained by promoting a 3s electron to the 3p orbital, to 2 2 6 obtain the 1s 2s 2p 3p 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.  Electronegativity increase from left to right across a period. (Highest F 4.0) Empirical Formula molecular formula  An empirical formula sh