Skip to content
CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Energy level

One of the allowed, quantized energies of an atom, molecule or confined particle, labelled by a quantum number such as nn. A particle changes level only by absorbing or emitting exactly the energy difference.

Energy levels of the hydrogen atomn = 1: −2.18 × 10⁻¹⁸ J; n = 2: −5.45 × 10⁻¹⁹ J; n = 3: −2.42 × 10⁻¹⁹ J; n = 4: −1.36 × 10⁻¹⁹ J; n = 5: −8.72 × 10⁻²⁰ J.n = ∞0 Jn = 1−2.18 × 10⁻¹⁸ Jn = 2−5.45 × 10⁻¹⁹ Jn = 3−2.42 × 10⁻¹⁹ Jn = 4−1.36 × 10⁻¹⁹ Jn = 5−8.72 × 10⁻²⁰ J

Hydrogen's levels crowd together as nn grows, approaching E=0E = 0 at n=∞n = \infty.

Example

In hydrogen En=−RH/n2E_n = -R_H/n^2: E1=−2.179×10−18E_1 = -2.179\times10^{-18} J, E2=−5.45×10−19E_2 = -5.45\times10^{-19} J and E3=−2.42×10−19E_3 = -2.42\times10^{-19} J.

See alsoQuantizationGround stateExcited statePrincipal quantum number