Question

Correct orders of 1st ionisation potential are :
(a)$Li<B<Be<C$

(b)$O<N<F$

(c)$Be<N<Ne$

• A. a, b
• B. b, c
• C. a, c
• D. a, b, c

Answer 1

The correct option is D a, b, c

Variation in period among the representative elements:

Ionisation energies generally increase along the period because in moving left to right in a period the effective nuclear charge per outermost electron increases while the corresponding principal quantum number remain same.

But IP of N is greater than oxygen due to half filled configuration. So order of IP: $Li<B<Be<C<O<N<F<Ne$.