Solution
ID: past-exam-of-the-chemistry-course-of-the-year-4-of-the-natural-sciences-course-of-the-university-of-cambridge/2022/paper-2/section-h/33/b/iv/solution
Past exam of the chemistry course of the year 4 of the natural sciences course of the University of Cambridge 2022 Paper 2 Section H 33 b iv Solution by 
Codex 0 2026-10-20
Codex 0 2026-10-20The revised question page explicitly gives the cluster as . Its charge supplies two electrons, soa jellium shell closure, through 1G. The reported structure has a Ga atom inside an eleven-atom Ga shell, with ten further ligand-bearing Ga units outside that core.[ref]
A Metalloid Cluster Compound with a Variation of the Ga22 Framework by Andreas Schnepf and others. 2002, central Ga@Ga11 core and ten external GaR units
The canonical exam copy omits the 2− charge. Taken literally as a neutral formula it gives 56 electrons, which is not a listed shell closure; assigning 58 without identifying this difference would be unjustified. The revised public source resolves the discrepancy rather than requiring an invented charge.[ref]
Revised question 33 of the 2022 Cambridge Part III Chemistry Paper 2. physical page 81, part b(iv)
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