Question

exam 2: periodicity & electron configuration/em spectrum
which sequence correctly places the elements in order of increasing (low to high) ionization energy?
o f, cl, br, i
o cl, f, br, i
o i, br, cl, f
o i, br, f, cl

Explanation:

Step1: Recall ionization - energy trend

Ionization energy increases across a period and decreases down a group in the periodic table. F, Cl, Br, and I are all in Group 17 (halogens). As we move down the group, the atomic size increases, and the out - most electrons are farther from the nucleus, making them easier to remove. So, the ionization energy decreases down the group.

Answer:

I, Br, Cl, F