Chemistry - PERIODIC TABLE Question with Solution | TestHub

I.E. increases across a period (left → right)

I.E. decreases down a group

Exceptions

Be > B (stable filled subshell)

N > O (half-filled stability)

(A) Na < Li < Be

Li has higher I.E. than Na (smaller size)

Be higher due to stable filled 2s²

Correct order

(B) Si < P < C < N

N highest (half-filled stability)

P < Si (down group effect)

C < N correct trend

Acceptable correct order

(C) C < O < O²⁺

O²⁺ has much higher I.E. (high nuclear charge, low electrons)

O > C true

Correct order

(D) P < Ar < Ne

Ne has highest I.E. in period

Ar > P true

Correct order

Final Answer: A, B, C, D