Final answer:
An electron at n = 2 and l = 1 has three possible magnetic quantum numbers corresponding to three p orbitals.
Step-by-step explanation:
An electron at n = 2 and l = 1 refers to the second energy level and the p orbital, as the angular momentum quantum number, l, of 1 corresponds to a p orbital. The number of orbitals for a given l is determined by the possible values of the magnetic quantum number, ml. These values range from -l to +l, inclusive. Therefore, for l = 1, the possible ml values are -1, 0, and +1, indicating that there are three p orbitals at this energy level.