Question

Which correctly summarizes the trend in electron affinity?

it tends to be very high for group 2
it tends to be more negative across a period
it tends to remain the same across periods
it tends to be more negative down a group

Answer 1

it tends to be more negative across a period

Step-by-step explanation:

We have to remember that the periodic table is arranged accordingly to the number of electrons that the elements have in their outer valance shell, so the closer you are to the right of the periodic table the closer you get to the elements taht have the most electrons in their outer valance shells, this means that they have a greater negative electron affinity, which means that the elements on the right are more willing to gain an electron.

Answer 2

The answer is it tends to be more negative down a group. This is because as you go down the periodic table, the elements have more electron shells in their atoms. This makes the outermost shells less attracted to the nucleus due to their greater distances from the nucleus. Therefore, these shells are less likely to attract electrons (hence lower electron affinity) and are even more likely to lose electrons from their outer electron orbits.