The Role of Eletrons
Electrons spin around the nucleus. they are called shells or energy levels which can be number by 1,2,3 and 4. and can also be named K, L, M and N.
An easy way to explain it would be if a pea was the nucleus,
it would sit in side a ping pong ball (the first shell),
and all of this would sit in a tennis ball (second shell)
and all of that would sit inside of a basketball (third shell)
and all of that would sit in side of a beach ball (fourth Shell)