The first ionization energies of the elements ________ as you go from left to right across a period of the periodic table,and ________ as you go from the bottom to the top of a group in the table.
A)increase, increase
B)increase, decrease
C)decrease, increase
D)decrease, decrease
E)The first ionization energies of the elements are completely unpredictable.

Question

Quizplus · Accepted Answer

As you move from left to right across a period of the periodic table, the number of protons in the nucleus increases and the atomic radius decreases. This makes it more difficult to remove an electron, so the first ionization energy increases. As you move from the bottom to the top of a group, the number of energy levels (shells) filled with electrons decreases, and the atomic radius decreases. This makes it easier to remove an electron, so the first ionization energy decreases.

The First Ionization Energies of the Elements ________ as You