Atomic structure

Planck’s Quantum Theory

Energy can be absorbed or emitted in a fixed amount called quanta.

Bohr’s Theory

Excess energy in the transition between ground and excited state, ∆E, is released in the form of light.

Line spectra of hydrogen atom

Lyman → Balmer → Paschen → Brackett → Pfund

Characteristics of electron in a ground state from Bohr’s theory

Stable and remains at its lowest energy orbital.

Aufbau Principle

Orbitals are filled in order of increasing energy from lowest level to highest level.

Pauli Exclusion Principle

No atomic orbital (one box) can contain >2 electrons and each orbital can have 2 electrons with spins paired (opposite spin directions).

Hund’s Rule

When there is a set of orbitals of equal energy, each orbital becomes half-filled before any of them becomes completely filled.