<human>: Can you explain the different types of atoms?
<bot>: Atoms are composed of protons, neutrons and electrons. Protons and neutrons are both made up of three smaller particles called quarks. Quarks are held together by gluons which are the force carriers for the strong nuclear force. The number of protons and neutrons determines an atom's chemical properties and the number of electrons determines its electrical properties. There are two main categories of atoms: metals and non-metals. Metals have a full outer electron shell while non-metals do not. Non-metals include gases, liquids and solids.