University:
Eastern Kentucky University
Course:
CHE 111 | General Chemistry
Academic year:

2020
Views:

204

Pages:

1
Author:

Alma Hester

General Chemistry 1: Atomic Structure A Z X A = Mass number = protons + neutrons Z= Atomic number = # of protons Note: Atomic Weight = weighted average Scientist Contributions Rutherford Model: 1911. Electrons surround a nucleus. Bohr Model: 1913. Described orbits in more detail. Farther orbits = !Energy Photon emitted when n¯, absorbed when n! Heisenberg Uncertainty: It is impossible to know the momentum and position simultaneously. Hund’s Rule: e- only double up in orbitals if all orbitals first have 1 e-. Pauli Exclusion Principle: Paired e- must be + " $, − " . # # Constants Light Energy #F 𝐸= Avogadro’s Number: 6.022$×$10 =1$mol Planck’s (h): 6.626$×$10HFI J•s ($) 𝐸 =h$𝑓 l 𝑓 =frequency h=$Planck 8 s$constant c=speed$of$light Speed of Light (c) 3.0$×$ K m 10 s AHED Mnemonic Absorb light Higher potential Excited Distant from nucleus Diamagnetic vs. Paramagnetic Diamagnetic: All electrons are paired ! ¯ REPELLED by an external magnetic field Paramagnetic: 1 or more unpaired electrons ! PULLED into an external magnetic field Follow Hund’s rule to build the atom’s electron configuration. If 1 or more orbitals have just a single electron, the atom is paramagnetic. If there are no unpaired electrons, then the atom is diamagnetic. Examples: He = 1s2 = diamagnetic and will repel magnetic fields. C = 1s22s22p2 = paramagnetic and will be attracted to magnetic fields. Quantum Numbers Quantum Number Name What it Labels n Principal e- energy level or shell number l Azimuthal 3D shape of orbital ml Magnetic Orbital sub-type ms Spin Electron spin Possible Values 1, 2, 3, … Notes Except for d- and f-orbitals, the shell # matches the row of the periodic table. Atomic Orbitals on the Periodic Table 0, 1, 2, …, n-1 0 = s orbital 1 = p orbital 2 = d orbital 3 = f orbital 4 = g orbital Integers –l ® +l " " + $, − # # Maximum e- in terms of n = 2n2 Maximum e- in subshell = 4l + 2 Free Radical: An atom or molecule with an unpaired electron. The Aufbau Principle 3D shapes of s, p, d, and f orbitals 1