The electron affinities, in kJ>mol, for the group 11 and group 12 metals are as follows: Cu -119 Zn 7 0 Ag -126 Cd 7 0 Au -223 Hg 7 0 (b) Why do the electron affinities of the group 11 elements become more negative as we move down the group? [Hint: Examine the trends in the electron affinities of other groups as we proceed down the periodic table.]