How does an atom become a positive ion? a negative ion?

So ions are atoms that have either gained or lost electrons to complete their energy levels.

In order for a positive ion to be formed, an atom must lose electrons.

In order for a negative ion to be formed, an atom must gain electrons.

When an atom loses and electron, it loses a negative charge and then becomes a positive ion.

explanation:

crosscutting concepts have application across all domains of science. as such, they are a way of linking the different domains of science. they include patterns; cause and effect; scale, proportion, and quantity; systems and system models; energy and matter; structure and function; and stability and change.