The atomic structure

• Protons are positively charged particles found in the nucleus of an atom.
• In a neutral atom, there are the same number of protons and electrons
• The atomic number of an element is the number of protons each atom of the element has.
• The Atomic mass number (or just mass number) is the number of protons and neutrons in an atom.
• Isotopes are atoms with the same number of protons but different number of neutrons.
• Ions are atoms that have lost or gained electrons.
• Cations form when at least one electron is lost (ion becomes positively charged).

  Anions form when at least one electron is gained (ion becomes negatively charged).
• A compound is formed by two or more elements chemically bonded together.
• Molecules are made up of two or more atoms joined together by chemical bonds.
• Compounds can be ionic compounds or covalent compounds.
• Molecules are compounds made up of two or more non-metal atoms joined together by covalent bonds.
• Compounds can be ionic, covalent or metallic.
• Non-metals react with other non-metals to produce an ionic compound.
• Metals are good conductors of electricity, while non-metals are poor conductors of electricity.
• Metalloids have properties between metals and non-metals.