* Compounds are formed when two or more elements chemically combine in a fixed ratio. For example, water (H₂O) is a compound because it always has two hydrogen atoms and one oxygen atom.

* Mixtures are combinations of two or more substances that are not chemically bonded. The substances in a mixture retain their individual properties.

In the case of salt water:

* Salt (NaCl) is a compound made up of sodium (Na) and chlorine (Cl) atoms.

* Water (H₂O) is also a compound.

When you dissolve salt in water, the salt crystals break down into individual sodium and chloride ions. These ions are surrounded by water molecules, but they don't form new chemical bonds. The salt and water retain their individual properties within the mixture. You can separate the salt from the water through evaporation, which wouldn't be possible if they were chemically bonded.