Which atom has the greater electron affinity, #"O"^(-)# or #"O"#?
1 Answer
Well, if you look at the definition, electron affinity is just the propensity to accept electrons.
It seems at first that
Actually, since
#"EA"_(1,"O") = -"142 kJ/mol"#
#"O"(g) + e^(-) -> "O"^(-)(g)#
#"EA"_(2,"O") = +"844 kJ/mol"#
#"O"^(-)(g) + e^(-) -> "O"^(2-)(g)# (the second electron affinity of
#"O"# is the first electron affinity of#"O"^(-)# )
If electron affinity is favorable, energy is released upon adding an electron, meaning it's negatively-signed. However, since
Therefore, the "greater" electron affinity (really, the more favorable electron affinity) is with