Atoms, Elements, Compounds

• • In atoms, the number of protons is equal to number of neutrons
  • In ions, the number of protons are not equal to number of neutrons
• • All substances made up of atoms
  • An atom is the smallest part of an element that can exist
• • Atoms have a radius of 0.1 nanometres
• • The nucleus contains protons and neutrons
  • The nucleus has a radius of 1 x 10^14 metres
  • The nucleus has a positive charge
• • Electrons are around the nucleus
  • Electrons are negatively charged
  • Electrons have very small mass
• • Protons have a charge of +1
  • Protons have a relative mass of 1
  • Neutrons have a charge of 0
  • Neutrons have a relative mass of 1
• • An isotope has the same number of protons but different number of neutrons
• • RAM = (sum of isotope abundance x isotope mass number) / sum of abundance of all isotopes