Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app

JEE Main 201912 AprilEvening Shift

Exam: JEE Main
Year: 2019
Date: 12 April
Shift: Evening Shift
Subject: Chemistry
Chapter: d and f Block Elements

JEE Main 2019 · 12 April · Evening Shift · Chemistry · d and f Block Elements

The pair that has similar atomic radii is:

The pair that has similar atomic radii is:

Options

A $Mo$ and $W$
B $Sc$ and $Ni$
C $Mn$ and $Re$
D $Ti$ and $Hf$

Correct answer

A. $Mo$ and $W$

Step-by-step solution

Among the given pairs Mo and W have the same atomic radius of

139pm

and this is due to Lanthanoid contraction.
This happens due to the poor screening ability of 4f electrons. The radius of other pairs are:

Sc ( 162pm ) andNi ( 124pm )

Mo ( 139pm ) andW ( 139pm )

Mn\left(140pm\right)andRe\left(135pm\right)

Ti\left(170pm\right)andHf\left(159pm\right) .

Practice d and f Block Elements on Quantrex Academy →

More from d and f Block Elements

Given below are two statements: Statement I: The number of pairs among [Ti^ 4+ , V^ 2+ ]… JEE Main 2026 Given below are two statements for catalytic properties of transition metals. Statement… JEE Main 2026 The correct order of first (Δ_i H_1) and second (Δ_i H_2) ionisation enthalpy values of… JEE Main 2026 The correct statements among the following are. A. Basic vanadium oxide is used in the… JEE Main 2026 Given below are two statements : Statement I: Presence of large number of unpaired… JEE Main 2026 A paper dipped in a dil. H_2SO_4 solution of ' X ' upon treatment with SO_2 gas turns… JEE Main 2026 Which of the following is NOT a physical or chemical characteristics of interstitial… JEE Main 2026 Pairs of elements with the same number of electrons in their respective 4f orbital are… JEE Main 2026 Full d and f Block Elements list All JEE Main PYQs