Atomic Structure

Relative MassRelative Charge

Working out the number of protons and neutrons examples:

  Protons Neutrons Electrons
79Br 35 44 35
81Br 35 46 35
35Cl 17 18 17
37Cl 17 20 17

Bromine has two isotopes. 50% of bromine is 79Br, and the other 50% is 81Br. Work out the average mass:

Useful books for revision:

Revise AS Chemistry for Salters (Written by experienced examiners and teachers of Salter's chemistry)
Revise AS Chemistry for Salters (OCR) (Salters Advanced Chemistry)