posted by K .
Consider the following neutral electron configurations in which 'n' has a constant value. Which configuration would belong to the element with the most negative electron affinity, E-ea?
b) ns^2 np^2
c) ns^2 np^5
d) ns^2 np^6
would the answer be "d"??? (as in, it would be a noble gas with a p^6, and then have a more negative e- affinity???)
If it is a noble gas, it has no affinity to attract an additional electron. I would examine the affintity of c) (as Fluorine, chlorine ).
Unless I am out of date or misunderstood the question I thought that all electron affinities were shown as positive values. Those ending np^5 (e.g fluorine or chlorine) have the highest electron affinities.
The electron affinity is defined as the amount of energy ABSORBED when an electron is added to an isolated gaseous atom to form an ion with a 1- charge. The convention is to assign a positive value when energy is absorbed and a negative value when energy is released. For example, Be(g) + e + 241 kJ ==> Be^-(g) EA = +231 kJ/mol. (endothermic)
Cl(g) + e ==> Cl^-(g) + 348 kJ/mol EA = -348 kJ/mol (exothermic)
I think c is the answer.
The answer is c) ns^2 np^5
I know this because in addition to the explanations posted, above I just did this for my chemistry homework. I'm guessing you also have Mastering Chemistry?