Electron affinity is the measure of how tightly an atom's nucleus holds it's valence electrons. have a strong electron affinity and have a weak electron affinity.

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).