Which types of orbitals are found in the principal energy level n = 2? a.) s b.) s, f c.) s, d d.) s, p e.) s, p, d

Remember this:

1) n is principal quantum number and represents the energy level.

2) l is the second quantum number and represent the type of orbital.

3) l can take values from 0 to n - 1

4) each number of l is associated with a type of orbital.  This table shows the equivalence:
 
l number       type of orbital

0                    s

1                    p

2                    d

3                     f

With that, you can tell that n = 2 permits l = 0 and 1, which is orbitals s and p.

Therefore, the answer is the option D) s, p.