Which element in each pair has a greater first ionization energy?

a) lithium, boron

b) magnesium, strontium

c) cesium, aluminum

A) Boron

Ionization energy tends to increase as we go from left to right in a period.

B) Mg

Ionization energy tends to decrease as we go down a group

C) Al

Ionization energy tends to increase as we go towards the top right of the periodic table.