Question

which of the following is not a possible sublevel? 1s 2p 3f 4d

Explanation:

In electron - shell theory, the sublevels are determined by the principal quantum number (n) and the angular - momentum quantum number (l). The possible values of l are from 0 to n - 1, corresponding to s (l = 0), p (l = 1), d (l = 2), f (l = 3). For n = 1, l can only be 0 (1s is valid). For n = 2, l can be 0 or 1 (2s and 2p are valid). For n = 3, l can be 0, 1, or 2 (3s, 3p, 3d are valid, but 3f is not since l = 3 is not allowed when n = 3). For n = 4, l can be 0, 1, 2, 3 (4s, 4p, 4d, 4f are valid).

Answer:

C. 3f