Explanation:
The number of subshell present are s, p, d, and f
The number of orbitals in each are as follows -
The number of orbitals can be calculated by the degeneracy, 2 l + 1 , where l denoted is angular momentum quantum number that determines the shape of an orbital. For s, p, d, and f the angular momentum quantum number is 0, 1, 2 3 respectively.
So, maximum number of f orbitals that are possible can be calculated as -
2 × l + 1 = 2 × 3 + 1 = 7