[GuB-42]

The general idea is actually quite intuitive. Sodium doesn't like being sodium (metal), and chlorine doesn't like being chlorine (gas), they are very angry and will do anything to change the situation. But they like it when they are together as salt and they are well behaved in this form. This is, of course very simplified.

An example I like is with nitrogen. Nitrogen atoms really want to form nitrogen gas (N2), a form that is really stable and therefore unreactive and generally harmless. However, if the nitrogen atoms are not in this form, and they have the opportunity to turn into it, they will, and they want it so much that it can be violent. That's why a lot of explosives are nitrogen-based, they are made of nitrogen atoms that have been separated from their N2 form by giving them a lot of energy, and when they come back together as the explosive is detonated, all that stored energy is released.

[Sharlin]

Even greatly simplified, it’s pretty important to understand the difference between a salt and a covalently bonded compound – sodium and chloride don’t really stay together, nice and inert; they disassociate readily in a solution. Salt water has individual sodium and chlorine ions freely floating around. But being ions now, both have gotten what they wanted, and are quite content and nonreactive now.