The energy of an electron in first Bohr's orbit of H atom is − 13.6 eV . The energy value of electron in the…

The energy of an electron in first Bohr's orbit of H atom is −13.6 eV. The energy value of electron in the first excited state of Li 2+ is :
  1. 27.2 eV
  2. −30.6 eV
  3. 30.6 eV
  4. −27.2 eV

Solution

For H atom & H like species
The electronic energy in the nth orbit is

E n = - 13.6 z 2 n 2 eV

E n Li 2 + = - 13.6 × 9 n 2 eV = - 122.4 eV n 2

If n = 2

E 2 Li 2 + = - 122.4 2 2 = - 30.6 eV

Asked in: MHT CET Full Test 3

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