Chemistry: electron configurations

Chemistry

Heisenberg uncertainty principle

One can’t know the position and velocity of electrons

Shroedinger Equation

Probability function - “where should we find the electron?” (90%)

Electrons are treated as waves - “particle - wave duality”

Shroedinger equation

Quantum Mechanics

n

principle quantum number → an integer (1, 2, 3, …)

l (as in lowercase L)

angular momentum number → an integer (0,1,2, n-1)

ml

magnetic quantum number → an integer (-l, 0 , +l)

ms

magnetic spin (+1/2, -1/2)

Pauli Exclusion Principle

no electrons have the same 4 quantum numbers

Aufbau

fill orbitals from lowest energy to highest energy

Hunds rule

if orbitals at the same sublevel (ml) are available; electrons will spread out, with parallel spins

Bor model

positive nucleus

orbits → electrons

Electrons

When excited, electrons will jump to a higher shell

When relaxed, they will go to a lower shell

Emission spectra

When electrons relax, going to the lower shell emits emission spectra

* Emission spectra emit energy in the form of a photon
* Each atom releases photons with characteristic energies
* Photons are like waves

**E = hv**

E

energy

h

Planck’s constant = 6.626 x 10^-34 Js

v

frequency (Hz or s ^-1)

C = v(lambda)

c = speed of light

lambda = wavelength (in m, or nm = 10^-9)

s orbitals

2 electrons

p orbitals

6 electrons

d orbitals

10 electrons