(A) : First ionisation energy of nitrogen is greater than oxygen.
(R) : Across a period effective nuclear charge decreases.

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

(A) is true but (R) is false

Both (A) and (R) are true but (R) is not the correct explanation of (A)

Both (A) and (R) are true and (R) is the correct explanation of (A)

Both (A) and (R) are false

answer is C.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

N⁷:1s²2s²2p³ ; O⁸ : 1s²2s²2p⁴

The ionisation energy of N is more than that of O because N has exactly half filled valence p orbital. In case of O, removal of an electron results in stable half filled electronic configuration. This requires less amount of energy.

The nuclear charge increases across a period. Hence, both the assertion and reason are false.

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!