c1- atomic structure

• Protons:

  • relative mass= 1
  • relative charge= +1
  • heavy compared to electrons
• Neutrons:

  • relative mass= 1
  • relative charge= 0
  • heavy compared to electrons
• Electrons:

  • relative mass= very small
  • relative charge= -1
  • tiny
• atomic number= number of protons / electrons

  mass number= number of protons+ number of neutrons

  mass of neutrons= mass number- atomic number
• In a positive ion: number of electrons= atomic number - charge

  In a negative ion: number of electrons= atomic number + charge
• Elements are made up of atoms with the same atomic number
• Isotopes are atoms with the same number of protons but a different number of neutrons.
• Compounds are different types of atoms bonded together