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The radius of the second Bohr orbit, in terms of the Bohr radius, a0, in Li2+ is:

1. 4a0/3
2. 2a0/9
3. 2a0/3
4. 4a0/9

Correct answer: 4a0/3

Solution

The Bohr orbit radius is r = (n^2/Z)*a0. For Li2+ (Z=3) and n=2, r = (4/3)*a0 = 4a0/3.

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