When non-metal atoms bond to other non-metal atoms they share electrons to form covalent bonds.
1.44 Sharing electrons
In the previous topic you will have seen how ionic compounds are formed when the atoms of metals transfer electrons to the atoms of non-metals. The electron transfer enables the atoms to fill their outer electron shells and become stable.
Here we consider what happens when atoms of non-metals bond with other atoms of non-metals.
Non-metal atoms tend to hold on to electrons and tend not to form positive ions. By sharing electrons the atoms' outer electron shells become full and therefore stable.
Assumed background knowledge: