Question

Incorrect order of atomic radius is?

Hint:

Remember that atomic radius increases as you move down a group and decreases as you move across a period. Always consider the group and period trends to determine the relative sizes of atomic radii.

Answer 1

(1) B < Al
(2) In < T l
(3) Al < Ga
(4) Ga < In

Atomic Radius Trends in the Periodic Table

Atomic radius changes predictably with element position:

Down a Group: Atomic radius increases with added electron shells.

Across a Period (Left to Right): Atomic radius decreases due to increased nuclear charge.

Evaluation of Given Pairs:

B < Al: Boron (B) and Aluminum (Al) are in Group 13. Al is below B, thus Al possesses a larger atomic radius. Correct.

In < Tl: Indium (In) and Thallium (Tl) are in Group 13. Tl is below In, thus Tl possesses a larger atomic radius. Correct.

Al < Ga: Aluminum (Al) and Gallium (Ga) are in Group 13. Ga is below Al, thus Ga possesses a larger atomic radius. Correct.

Ga < In: Gallium (Ga) and Indium (In) are in Group 13. In is below Ga, thus In possesses a larger atomic radius. Correct.

Conclusion: All evaluated orders are correct based on general atomic radii trends in the periodic table. The initial reasoning contained an error. Indium, situated below Gallium within the same group, exhibits a larger atomic radius.