Chemistry

• mass number 


  the total number of neutrons and protons in an atom. add together to get the mass number of atoms
• atomic number 


  the number of protons in the nucleus. the periodic table is organised by the atomic number
• atomic mass 


  tells you how much an atom of an element weighs. calculated using the relative abundance of isotopes in a natural occurring element
• isotopes 


  atoms with the same number of protons but different numbers of neutrons
• where is the atomic number/ electron in the periodic table

  at the bottom of the element
• mass number in the periodic table 


  at the top of the element
• abundance 


  how common each isotope is