* Elements are pure substances that cannot be broken down into simpler substances (like oxygen, gold, or carbon).

* Compounds are formed when two or more elements chemically combine in a fixed ratio (like water, H₂O, or salt, NaCl).

* Mixtures are combinations of two or more substances that are not chemically bonded. They can be separated by physical means.

Dust is made up of many different things:

* Tiny particles of dirt, sand, and soil

* Dead skin cells

* Pet hair and dander

* Pollen

* Fibers from clothing and carpets

* Tiny bits of food

These components are not chemically bonded together, and their proportions can vary greatly depending on the environment. You can even separate some components of dust using methods like a vacuum cleaner or a filter.