Answer:
The main energy levels are the shells where the electron resides in a location that's relative to the atom's nucleus.
Step-by-step explanation:
In electronic configuration in chemistry, the main energy levels are the shells where the electron resides in a location that's relative to the atom's nucleus. Such an energy level is usually denoted by the principal quantum number n. So n can be 1,2,3,4...e.t.c