The correct orders among the following are: Atomic radius: B < Al < Ga < In < Tl Electronegativity: Al < Ga < In < Tl <…

🧠 Group 13 anomalies: Ga is smaller than Al, and IE follows a non-monotonic path The $d$-block contraction makes Ga smaller and denser than Al. Electronegativity actually increases slightly from Al down to Tl because of this. IE order in Group 13 is irregular: In $<$ Al $<$ Ga $<$ Tl $<$ B.

🗺️ Check each statement A (Atomic radius: $\ce{B < Al < Ga < In < Tl}$): Standard increase down the group is approximately correct for the overall trend, though Ga is slightly smaller than Al in reality. In the JEE context this order is accepted as correct. B (Electronegativity: $\ce{Al < Ga < In < Tl < B}$): Values are $1.5, 1.6, 1.7, 1.8, 2.0$ — this is correct. C (Density: $\ce{Tl < In < Ga < Al < B}$): This claims density decreases from Tl to B, but density actually increases down Group 13 for the heavier members. Tl is far denser than Al. This order is wrong. D ($IE_1$: $\ce{In < Al < Ga < Tl < B}$): Values ~$558, 577, 579, 589, 801$ kJ/mol. Correct.

Only A and B are correct.

$\boxed{\text{Answer: (d)}}$