Atoms

• Atomic number - number of protons.
• radius of an atom - 1x10 (to the power of -10) m
• mass number - number of protons/electrons + number of neutrons.
• There are 3 isotopes of hydrogen - deuterium, tritium and protium (which is the most common)
• 1 mole of any substance is equal to 6.02 x 10^23 atoms : This is called the Avogadro constant
• Delocalised electrons: electrons that are not bound to the nucleus of an atom and can move freely around the atom