They are not available to make bonds with other atoms.

It is possible for particles to join with other atoms.

It has no bonds left to connect with other atoms.

I filled it with molecules and atoms, all in different colors.

It is even possible to work with single atoms.

As an example, all matter is built with atoms, yet all material things are different.

Sometimes they rejoin with atoms for a while, only to be let loose again later on.

The free space is packed with cubical atoms of energy.

They can gain an electron by reacting with atoms of other elements.

Gaussians are typically used in molecules with three or more atoms.