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Discuss periodic trends in the Lewis acidity of metal ions.
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Explain what we mean by hard and soft acids and bases, using specific examples.
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Explain why hard and soft should not be equated with electrostatic and covalent.
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According to HSAB theory Cu and Zn are classiﬁed as intermediate acids while Cd is classiﬁed as soft. The base (CH
2
)
4
O is considered hard while (CH
2
)
4
S is soft. Using E and C numbers for Cd[N(Si(CH
3
)
3
]
2
and ZnTPP calculate the enthalpies for these two acids interacting with (CH
2
)
4
O and (CH
2
)
4
S and show that the HSAB model correctly predicts which base interacts more strongly with which acid. Do the same comparison using Cu(HFacac)
2
as the acid and show that HSAB fails to predict which base interacts more strongly. How are these results related to the Cramer-Bopp plot that show one property or one parameter cannot be used to rank Lewis acid or base strength?