12.1 Electrons in atoms

Emission Spectra and ionization

• First ionization energy IE₁ relates to process:
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• Second IE is
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• N^th ionization energy IE_n relates to process:
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  • IE₁ < IE₂ < IE₃ < IE₄ …
• In emission spectrum, the lines converge at higher energies. At the limit of convergence, the lines merge forming a continuum
• Beyond continuum, electron can have any energy
• The frequency of the radiation in the emission spectrum at the limit of convergence can be used to determine IE₁

Periodic Trends in ionization energies

• In Ca, big jump between IE₂ and IE₃ because corresponds to removing electron from fully occupied 3p sublevel
• In Ti, big jump between IE₄ and IE₅ because change in energy level. Ti⁵⁺ does not occur naturally
• Ionization energy for Ti increases more gradually than Ca because electrons are being removed from 3d and 4s orbitals, which are much closer in energy than 3p and 4d.
• These big jumps in energy occur when removal of electrons from different energy levels n (1,2,3,4,…)