Atoms, Elements and Compounds: an atom has a central nucleus (protons and neutrons) surrounded by electrons.
The proton (atomic) number equals the number of protons. An element is made of one type of atom; a compound is two or more elements chemically joined; a mixture is not chemically joined.
Remember
- Protons +, electrons −, neutrons neutral.
- Element = one atom type; compound = elements chemically bonded.