(a) state the relative charges and approximate relative masses of a proton, a neutron and an electron (b) *describe, with the aid of diagrams, the structure of an atom as containing protons and neutrons (nucleons) in the nucleus and electrons arranged in shells (energy levels) (no knowledge of s, p, d and f classifi cation will be expected; a copy of the Periodic Table will be available in Papers 1 and 2) (c) defi ne proton number and nucleon number (d) interpret and use symbols such as 12 6C (e) defi ne the term isotopes (f) deduce the numbers of protons, neutrons and electrons in atoms and ions from proton and nucleon numbers (g) state that some isotopes are radioactive
