Question

The period with electrons in the shells K , L and M

Answer 1

In chemistry and atomic physics, an electron shell, or a principal energy level, ... The electron shells are labeled K, L, M, N, O, P, and Q; or 1, 2, 3, 4, 5, 6, and 7.

Answer 2

Hey friend.
The electron in the period K, L , M are :-
we know the formula 2n² , here n is the number of electron.
 
In K shell → 2n² = 2 × 1² = 2 electron
In L shell  → 2n² = 2 × 2² = 8 electron
In M shell → 2n² = 2 × 3² = 16 electron.

 expect it helps you :-)  {Mark as Brainliest}