How does increased electron shielding affect atomic radius as you move down a group in the periodic table?

• A. Atomic radius decreases because increased shielding causes electrons to be pulled closer to the nucleus.
• B. Atomic radius fluctuates unpredictably due to electron shielding effects.
• C. Atomic radius increases because additional electron shells cause greater shielding, reducing the effective nuclear charge felt by outer electrons.
• D. Atomic radius remains constant because electron shielding balances out the addition of new shells.

Answer: (C)

Verified step by step guidance

1. Understand that electron shielding refers to the phenomenon where inner electrons reduce the effective nuclear charge experienced by outer electrons.
2. Recognize that as you move down a group in the periodic table, new electron shells are added, increasing the distance between the nucleus and the outermost electrons.
3. Note that the increased number of inner electron shells causes greater shielding, which decreases the effective nuclear charge felt by the outer electrons.
4. Because the outer electrons feel less pull from the nucleus due to shielding, they are held less tightly and can spread out more, leading to an increase in atomic radius.
5. Therefore, the atomic radius increases down a group primarily because the effect of added electron shells and increased shielding outweighs the increase in nuclear charge.