BONDING
In order for a group of atoms to "stick" together, they must chemically bond.
Atoms do this in 3 main ways:
Ionic Bonding: this involves the transfer of electrons from one atom to the other in order to fully fill the outer most electron shell of the atom, and thus make it stable. ***All atoms want to be stable.***
The diagrams below illustrates the process:
The Sodium atom on the left (Na) has an extra electron, whereas the Chlorine atom on the right (Cl) lacks an electron, thus Sodium gives Chlorine an electron.
Once this happens the two create an ionic bond between themselves that would be represented as [Na]+[Cl]-