When an atom gains or loses a valence electron, it becomes a charged particle called a/an

When an atom gains or loses a valence electron, it becomes a charged particle called an ion.

In fact, an ion is an atom that has lost or gained a valence electron. As a result, the atom becomes positively charged (if it has lost an electron, and in this case it is called positive ion), or negatively charged (if it has gained an electron, and in this case it is called negative ion).

Fitness is the ability to perform only very light levels of physical activity.