Idon’t understand this, can you me?

An atom becomes stable if it has a full and complete ring. 2 of the choices are wrong off the start because you can't gain electrons and have a net positive charge, nor can you lose electrons and have a net negative charge. That leaves us with Option A or D. As I said earlier, an atom becomes stable if it has a full and complete ring. Obviously, if you lose 3 electrons from the last ring, the atom would be stable (because the 2nd ring is now full), and it also would have a net positive charge because it lost electrons.

The particles move faster because heat causes the atoms to speed up and move farther from each other.