use bond energies (\(\Delta H\) positive, i.e. bond breaking) to calculate enthalpy change of reaction, \(\Delta H_r\)

describe, and write equations for, the reactions of the elements with oxygen (to give Na₂O, MgO, Al₂O₃, P₄O₁₀, SO₂), chlorine (to give NaCl, MgCl₂, AlCl₃, SiCl₄, PCl₆) and water (Na and Mg only)