Question

For an atom’s electrons, how many energy sublevels are present in the principal energy level n = 4?

Answer 1

"n" represents principal energy level or principal quantum number. Principal energy levels are then subdivided into sublevels. The level of principal energy level is always equal to number of sublevels. Therefore if principal energy level = 4, then there are also 4 sublevels present, namely: 4s, 4p, 4d and 4f sublevels.