atoms and isotopes

• Element


  A substance made of one type of atom only
• Atomic number


  The number of protons in the nucleus of an atom. Also called the proton number
• Proton


  Subatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1
• Mass number


  The number of protons and neutrons found in the nucleus of an atom
• Neutron


  Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0
• Isotope


  Atoms of an element with the same number of protons and electrons but different numbers of neutrons
• Isotopes are forms of an element that have the same number of protons but different numbers of neutrons
• Isotopes of hydrogen


  • Hydrogen
  • Deuterium (hydrogen-2)
  • Tritium (hydrogen-3)
• Isotopes of carbon


  • 12 6 C
  • 13 6 C
  • 14 6 C
• 14 7 N and 14 6 C are not isotopes of each other, because although they have the same mass number, they are not the same element
• If the number of protons changes, then it is a different element
• 14 6 C contains six protons
• 14 6 C contains eight neutrons