JEE Main 2026 Jan 23 Shift 1, Chemistry Q19: Periodicity In Atomic Properties

JEE Main2026Jan 23, Shift 1Chemistry

The correct statements from the following are :

(A) Ionic radii of trivalent cations of group 13 elements decreases down the group.

(B) Electronegativity of group 13 elements decreases down the group.

(D) The trichloride and triiodide of group 13 elements are covalent in nature.

Choose the correct answer from the options given below :

Solution

(A) False: ionic radii of M $^{3 +}$ ions increase down group 13 (B $^{3 +}$ $<$ Al $^{3 +}$ $<$ Ga $^{3 +}$ $<$ In $^{3 +}$ $<$ Tl $^{3 +}$ ).

(B) False: electronegativity in group 13 follows the irregular order B $>$ Tl $>$ In $>$ Ga $>$ Al, not a monotonic decrease.

(D) True: due to small charge density and Fajans' rules, group 13 trichlorides and triiodides are predominantly covalent.

$∴$ C and D only.

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