chem key terms

• isotope

  atoms of the same element with different numbers of neutrons and different masses
• relative isotopic mass


  the mass of an isotope relative to 1/12th the mass of an atom of C-12
• relative atomic mass 


  the weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of C-12
• standard solution 


  a solution of known concentration
• ionic bonding 


  the electrostatic attraction between positive and negative ions
• first ionisation energy


  energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form a gas 1+ ion
• heterolytic fission


  the fission of a bond where both electrons move to one element to form two ions
• homolytic fission


  the fission of a bond where the electrons split, one to each element forming two radicals
• radical


  species with an unpaired electron
• photolysis


  splitting of a covalent bond using UV radiation as energy
• stereoisomerism


  molecules with the same structural formula but atoms are arranged differently in space
• nucleophile


  species attracted to areas of positive charge