Question

Correct order of first IP among following elements Be, B, C, N, O is
(a) B < Be < C < O < N (b) B < Be < C < N < O
(c) Be < B < C < N < O (d) Be < B < C < O < N

Answer 1

Explanation:

the correct answer is C

Be4.. b5 .. c6.. N7 ..O8

Answer 2

(d) Be < B < C < O < N

Explanation:

Be – 1s²2s²

B – 1s²2s²2p¹

C – 1s²2s²2p²

N – 1s²2s²2p³

O – 1s²2s²2p⁴.

IP increases as we go from left to right of a period. IP of Be > B. Further IP of O < N because atoms with fully or partly filled orbitals are most stable and hence have high ionization energy.

Option D is the answer.