2d orbital can’t exist in an atom. We can explain it from its subsidiary quantum number and principle quantum number (n). The value ℓ gives the sub-shell or sub-level in a given principle energy shell to which an electron belongs.

For n=2, ℓ=0, 1

i.e. The second principle energy level consists of two sub-shell which is 2s (ℓ=0) and 2p (ℓ=1). So, 2d orbital can’t exist.