Question

When atoms gain or lose electrons what do they become?

Answer 1

Ions - an ion is an atom or molecule which has gained or lost electrons.

Explanation:

Atoms and chemical species lose or gain electrons when they react in order to gain stability. Thus, typically, metals (with nearly empty outer shells) lose electrons to non-metals, thereby forming positive ions.

The number of electrons depends on their position on the Periodic table (in simple terms). for example, group I metals lose one electron to form +1 ions, group II lose 2 electrons to form +2 ions etc. non-metals gain electrons from metals in order to achieve full outer shells - GVII gain 1 to form 1- ions, GVI gain 2 to form 2- ions etc. Thus, metals will typically react with non-metals, exchanging electrons to form ionic compounds.