Chemistry · Periodicity of Elements and Periodic Properties

JEE Main 2026 — 5 April, Evening Shift — Question 51

The covalent radii of atoms $A$ and $B$ are $r_{A}$ and $r_{B}$ , respectively. The covalent bond length and total length of AB molecule are respectively :

Option A:
$\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right), 2\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$
Correct
Option B:
$\frac{1}{2}\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right),\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$
Option C:
$\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right),\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$
Option D:
$2\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right), \frac{1}{2}\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$

Answer: A

Step-by-step solution

According to NCERT Bond length $=\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}$ Total length of molecule $=2\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$

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Exam: JEE Main 2026
Paper: 5 April, Evening Shift
Subject: Chemistry
Chapter: Periodicity of Elements and Periodic Properties
Topic: Periodicity in Physical Properties (shielding and sizes)