Question

which element is having highest ionization potential and electron affinity?

Answer 1

Nobel gases have high ionisation energy because their outermost shell is fully filled. They resist to lose electrons. He is having the highest I.E.
Chlorine has the highest electron affinity. This is because of the appropriate size of chlorine. As we move down the group electron affinity decreases. In this way, fluorine should have the highest electron affinity. But this is an exception that chlorine has the highest electron affinity. The size of fluorine is very small that due to electron electron repulsion, it become unstable.