HL Paper 3
Nuclear reactions transform one nuclide into another. Fission, splitting a large nucleus into two smaller nuclei, releases vast amounts of energy.
(i) Uranium hexafluoride, UF6, is used in the uranium enrichment process that produces fuel for nuclear reactors.
State the molecular shape of uranium hexafluoride.
(ii) Explain why uranium dioxide, UO2, has a very high melting point whereas uranium hexafluoride vapourises easily into gas.
Markscheme
i
octahedral
Accept “square bipyramidal”
ii
UO2 strong bonding throughout crystal structure
UF6 molecular «covalent bonds between atoms» AND London/dispersion/instantaneous induced dipole-induced dipole forces between molecules
Accept “UO2 has ionic lattice”
Examiners report
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