Made up of protons, neutrons and electrons. Have their own symbol in the Periodic table. Can join together with other atoms. They make compounds. The protons and neutrons make up the nucleus. This is in the middle of the atom. It is positively charged. The electrons orbit the nucleus. They are negatively charged.
Electrons are arranged in energy levels. The first energy level contains 2 electrons. The second contains 8. The third contains 8. The fourth contains 8. Atoms that have one or seven electrons in it's outermost shell are more reactive then an atom with 3 or 4 electrons in it's outermost shell.
When a metal and a non-metal bond, they transfer electrons. This moving of electrons gives the atom(s) an overall charge. The metal loses 1,2 or 3 electrons. This gives it an overall charge of 1+, 2+ or 3+, as there are more protons then electrons. A non-metal gains electrons from the metal. This means that it has more electrons then protons, and thus it becomes a negative atom…