Question

13 question answer please please please

Answer 1

Option A is true.
You can justify by taking example.

Let 2s and 2p be two orbits.
Here n+l value of 2s is 2+0
and 2p is 2+1

As we can see that 2s has less n+l value than 2p thus electron will occupies 2s first.

Hope you get your answer.