JEE Main 2026 — p Block Elements (Group 13 & 14) Question with Solution
JEE Main 2026 (23 January Shift 1)
Question
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.
C. Among the group 13 elements, Boron has highest first ionisation enthalpy.
D. The trichloride and triiodide of group 13 elements are covalent in nature.
Choose the correct answer from the options given below :
A. Ionic radii of trivalent cations of group 13 elements decreases down the group.
B. Electronegativity of group 13 elements decreases down the group.
C. Among the group 13 elements, Boron has highest first ionisation enthalpy.
D. The trichloride and triiodide of group 13 elements are covalent in nature.
Choose the correct answer from the options given below :
Choose an option
Show full solutionCorrect option: A
Correct answer
AC and D Only
Step-by-step explanation
Analyzing statements about Group 13 elements (B, Al, Ga, In, Tl):
A. Ionic radii of M³⁺ cations: Down a group, more electron shells are added, so ionic radii increase, not decrease. FALSE
B. Electronegativity: Generally decreases down the group, though Ga shows an anomaly with higher electronegativity than Al. The statement is approximately true but has exceptions.
C. First ionization enthalpy: B (800.6 kJ/mol) is highest due to smallest size and highest nuclear charge density. Al (577.5), Ga (579), In (558), Tl (589). TRUE
D. Trichlorides and triodides: BCl₃, AlCl₃, GaCl₃, etc. are all covalent compounds (electron-deficient). BI₃, AlI₃, GaI₃, etc. are also covalent (I⁻ is large and polarizable). TRUE
The clearly correct statements are C and D.
A. Ionic radii of M³⁺ cations: Down a group, more electron shells are added, so ionic radii increase, not decrease. FALSE
B. Electronegativity: Generally decreases down the group, though Ga shows an anomaly with higher electronegativity than Al. The statement is approximately true but has exceptions.
C. First ionization enthalpy: B (800.6 kJ/mol) is highest due to smallest size and highest nuclear charge density. Al (577.5), Ga (579), In (558), Tl (589). TRUE
D. Trichlorides and triodides: BCl₃, AlCl₃, GaCl₃, etc. are all covalent compounds (electron-deficient). BI₃, AlI₃, GaI₃, etc. are also covalent (I⁻ is large and polarizable). TRUE
The clearly correct statements are C and D.
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This is a previous-year question from JEE Main 2026, covering the p Block Elements (Group 13 & 14) chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.