Older MCQs might not have the typical A, B, C,
D
choices. They
have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such
combinations to the answer.
A
1, 2 and 3 are correct
B
1 and 2 only are correct
C
2 and 3 only are correct
D
1 only is correct
describe, in simple terms, the lattice structure of a crystalline solid which is: (a) giant ionic, including sodium chloride and magnesium oxide (b) simple molecular, including iodine, buckminsterfullerene \( C_{60} \) and ice (c) giant molecular, including silicon(IV) oxide, graphite and diamond (d) giant metallic, including copper
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
