Expert: Dr. Henry Boyter, Jr. - 12/13/2006

Question
What happens to the charge on an atom when it loses an electrons?Why?

Answer
An atom is composed of electrons (negatively charged), protons (positively charged), and neutrons (neutral).  If you lose electrons from an atom, there is a surplus of positive charges compared to the negative charges and you get a positively charged atom, also called a cation.

So if Na loses one electron, you get Na+

if Ca loses two electrons, you get Ca+2.

on the other hand if an atom gains an electron:

If Na gains an electron you get Na- (called an anion)

The number of electrons gained or lost depends on the atom's position in the periodic chart and the circumstances that occur at the time.

Note that when you lose or gain electrons you keep the same number of protons and electrons, so the type of atom stays the same.  The type of atom is determined by the number of protons.  This is the most common form of change.

An entire different field of chemistry has to be studied for changes in proton and neutron numbers.  It is less common and you will study it later.