Answer the following question given this paragraph: 

All compounds form when atoms of different elements share or transfer electrons. In water, the atoms share electrons. In some other compounds, called ionic compounds , atoms transfer electrons. The electrons actually move from one atom to another. When atoms transfer electrons in this way, they become charged particles called ions. The ions are held together by ionic bonds.


Q: When electrons move from one atom to another, they become what?


A:
ions