Question

Which of the following factors contributes to the decrease in ionization energy within a group in the periodic table as the atomic number increases?

Answer 1

The decrease in ionization energy within a group in the periodic table is due to the shielding effect and increased atomic size as we move down the group.

Step-by-step explanation:

The decrease in ionization energy within a group in the periodic table as the atomic number increases can be attributed to two main factors:

1. Shielding effect: As we move down a group, the number of inner electron shells increases. These inner electrons shield the valence electrons from the attractive force of the nucleus. As a result, the valence electrons are less strongly attracted and require less energy to be removed.
2. Increased atomic size: Within a group, atomic size increases as we move down. The outermost electrons in larger atoms are farther away from the nucleus, resulting in weaker attraction. This makes it easier to remove these electrons, leading to a decrease in ionization energy.

Answer 2

The increase in Atomic radius contributes to the decrease in ionization energy down a group. As you go down a group the Atomic radius increases meaning more energy levels are being added, and there are more electron shieldings. So, therefore, electron shielding blocks the pull of the nucleus from the valence electrons and it makes easier for the atom to lose its outermost electron. So the atom needs less ionization energy to remove its valence electron.