λ
Summary: Modern Physics
Equations

E = hf

KE = ½ mv 2

De Broglie’s Equation: λ = ℎ 𝑚𝑣

C = f λ
Constants

C = 2.9979 x 10 8 m/sec

H = 6.626 x 10 -34 J*sec

M e
= 9.11 x 10 -11 kg

N
A
= 6.022 x 10 23 atoms
Electron Behavior


Aufbau Principle: Fill the lowest orbital first
Pauli Exclusion Principle: No more than 2 electrons can have the same set of four quantum numbers

Hund’s Rule: Lowest energy state has the maximum number of unpaired electrons
Electron Configuration

Orbitals: s,p,d,f

S begins at 1, has 1 orbital, holds 2 electrons

P begins at 2, has 3 orbitals, holds 6 electrons

D begins at 3, had 5 orbitals, holds 10 electrons

F begins at 4, has 7 orbitals, holds 14 electrons
Quantum Numbers


Quantum numbers (n , l, ml , ms) n, the principle Quantum number o the energy level of the atom

l, the Angular Momentum Quantum Number o Each value of l corresponds to a different subshell (s = 0, p =1, etc;) o L can be no greater than n-1
 m l
, the Magnetic Quantum Number o specifies which orbital within a subshell the electron is assigned to o ranges from [ – l, + l ]

 m s
, The Spin Quantum Number o specifies angular momentum of the electron o either + ½ or – ½ o indicated by the spin up the last electron (up spin + ½ down spin – ½ )
Terminology

Isoelectric: atoms having the same electron configuration

Paramagnetism: Attraction to a magnetic field. The atoms of paramagnetic substances contain unpaired electrons. Paramagnetic substances increase in mass when exposed to a magnetic field

Diamagnetism: Repelled by a magnetic field. Diamagnetic substances contain paired electrons
Periodic Trends

Atomic radii decreases, ionization energy increases, electron affinity increases, and electronegativity increases across the rows

Atomic radii increase, ionization energy decreases, electron affinity decreases, and electronegativity decreases down a column
Oxidation

Loses an Electron – Oxidized (ex: Fe +2 )

Gains an Electron- Reduced (ex: S -3 )

Oxidized molecule donates electron to reduced molecule