Quantum Theory & Electronic Structure of Atoms

Cations

positively charged atoms

Anions

negatively charged atoms

Planck’s Quantum Theory

atoms and molecules could emit and absorb only in discrete and definite quantities small packages or bundles

Photoelectric Effect

emission of electrons from certain metals when they are exposed to light of at least a certain minimum frequency

Frequency

number of waves per second that pass a particular point in space

Bohr’s conclusions

• each electron lies a definite radius from the nucleus and has a fixed amount of energy

• an electron can jump up in energy levels provided sufficient energy

• when it drops back down it emits light of a definite wavelength

Wave function

variable quantity that mathematically describes the wave characteristics of a particle

Principal quantum number

(shells) defines energy level

Angular momentum quantum number

(subshells) tells us the shape of the orbitals

Magnetic quantum number

describes the orientation of an orbital in space and therefore the number of each orbital in each subshell

Spin quantum number

indicates the spin of the electron

Aufbau’s principle

electrons will always occupy the lowest energy available

Pauli’s Exclusion principle

each orbital can only house only two electrons and will have opposite spins

E.S of Chromium

1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d ⁵

E.S of Copper

1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d ¹⁰