i know that the number of sublevels is equal to the principal energy levels but i dont really understand what this question is asking.
-
Assuming you mean SUBSHELLS, then the number of subshells of a principal energy level n is: 0 to n-1. If it is the first shell, then there is only one subshell, l=0. If it is then second shell, there are two subshells, l = 0 and 1. The number of subshells, then, is equal to the energy level.