Emission Spectra & Electronic Structure of Atoms

Emission

The release of energy (usually light) by an atom or molecule when electrons fall from a higher energy level to a lower one

Absorption

The uptake of energy (light) by an atom or molecule when electrons move from a lower energy level to a higher one

Wavelength

• The distance between successive wave peaks

• Usually measured in nanometres (nm) or meters (m)

• Longer wavelength → lower energy; shorter wavelength → higher energy

Wavenumber (ν̄)

• The number of waves per unit distance.

• Equal to 1 / wavelength.

• Units: cm⁻¹

• Higher wavenumber → higher energy