Question

how
many
orbitals possible for n=4?​

Answer 1

There are n 2 orbitals for each energy level. For n = 1, there is 1 2 or one orbital. For n = 2, there are 2 2 or four orbitals. For n = 3 there are nine orbitals, for n = 4 there are 16 orbitals, for n = 5 there are 5 2 = 25 orbitals, and so on