Question

Why 2d does not exist?

Answer 1

Answer:

Because the quantum number n must be superior to angular momentum quantum number. In the 2nd energy level, electrons are placed only in the 's' and 'p' sublevels, so there is no 'd' orbital. i.e. The second principal energy level consists of two sub-shell which is 2s (ℓ=0) and 2p (ℓ=1). So, 2d orbital can't exist.