Chemistry ET's 8 & 9

n

Principal: distance of e^- (negatively charged electron) from nucleus and the energy level of the elecron = the shell = positive integer cannot be 0 or negative Ex. n=1, 2, 3 etc. Larger numbers mean higher energy and greater distance from the nucleus

l

angular momentum: the shape of the orbit = the subshell (s,p,d,f) = from 0 to n-1 Ex. l= 0, 1, 2…

• l = 0 corresponds to an s subshell (spherical)

• l = 1 corresponds to a p subshell (dumbbell)

• l = 2 corresponds to a d subshell

• l = 3 corresponds to an f subshell

m_l

Magnetic: orientation of the orbit = the orbital = 0 ± l Ex. m_l = -l …, 0,… + l

m_s

spin of the electon = +1/2 or -1/2

Aufbau (A-U)

Electrons fill from the ground state up (A-U)

Pauli

No two electrons have the same quantum number (no two of the same letters in Pauli)

Hund

Put only one electron in the degenerate orbital first. Then, add one more electron with an opposite spin to each orbital. This applies to p and d subshells because they have degenerate orbitals. (Shortest name longest theory)

Degenerate Orbitals

orbitals in a subshell with the same amount of energy

The primary trend is….

a diagonal across the Periodic Table (To rank: follow atoms from bottom left (smallest) to top right (largest))

Electronegativity (EN)….

increases from lower left to the upper right across the periodic table.

Electronegativity (EN) values

H=2.1 HE=-- Li=1.0, Be=1.5, B=2.0, C=2.5, N=3.0, O=3.5, F=4.0, and Ne=— ( EN values (EXCEPT H, He, & Ne) increase by .5)

ΔEN

ΔEN = | EN₁- EN₂ | (insert electronegativity (EN) values that you should have memorized)