How many orbitals are there in the shell with n = 4?

16

Explanation:

The number of orbitals can be calculated when energy level is given.

For example:

n = 4

So in 4th energy level number of orbitals are,

n² = 4² = 16

There are 16 orbitals when n=4

One is 4s three are 4P five is 4d and seven are 4f.

while the number of electrons in energy level can be calculated as

2n²

n is energy level.

For n=4

number of electrons are,

2 (4) ² = 32