determine the electronic configuration of atoms and ions given the atomic or proton number and charge, using either of the following conventions: e.g. for Fe: \( 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2 \) (full electronic configuration) or \( [Ar] 3d^6 4s^2 \) (shortband electronic configuration)

state and explain the variation in the oxidation number of the oxides (Na₂O, MgO, Al₂O₃, P₄O₁₀, SO₂ and SO₃ only) and chlorides (NaCl, MgCl₂, AlCl₃, SiCl₄, PCl₆ only) in terms of their outer shell (valence shell) electrons