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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Series limit

The shortest-wavelength (highest-energy) line of a series, reached as ni→∞n_i \to \infty, where the lines crowd together. Its energy, Z2RH/nf2Z^2R_H/n_f^2, is the energy needed to ionize the atom from the lower level nfn_f.

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 = 6: −6.05 × 10⁻²⁰ J; n = 7: −4.45 × 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 Jn = 6−6.05 × 10⁻²⁰ Jn = 7−4.45 × 10⁻²⁰ J

The levels bunch up just below n=∞n = \infty (E=0E = 0).

Example

The Lyman limit, 91.2 nm, corresponds to RH=2.179×10−18R_H = 2.179\times10^{-18} J per atom, or 1312 kJ/mol: exactly the first ionization energy of hydrogen.

See alsoLyman seriesBalmer seriesIonization energyRydberg equation