Question

what are energy sublevels

Answer 1

Does SPD orbitals ring a bell?...i think that's what it has to do with, but i don't want to explain unless that seems semi-correct to you

Answer 2

Electrons revolves in their energy levels. every energy level have different in their energies from other levels.. the energy levels are accordingly devided into sub energy levels denoted by the letters s,p,d,f,... The number of sub level in a given energy level is equal to its value of 'n' for example; with in a principal energy level (n=2) i.e second energy level, two sub levels are possible which are s,p. every sub energy level has its own capacity