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

(A) $\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right), 2\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$

(B) $\frac{1}{2}\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right),\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$

(C) $\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right),\left(\mathrm{r}_{\mathrm{A}}+\mathrm{r}_{\mathrm{B}}\right)$

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

JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Chemical Bonding and Molecular Structure

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 :

Answer: (A)

The covalent bond length of A

-

B is the internuclear distance, which equals the sum of the two covalent radii,

r_{A} + r_{B}

. The overall length of the molecule runs from the outer edge of atom A to the outer edge of atom B, adding one radius beyond each nucleus:

r_{A} + (r_{A} + r_{B}) + r_{B} = 2 (r_{A} + r_{B})

. Hence the covalent bond length is

(r_{A} + r_{B})

and the total length of the AB molecule is

2 (r_{A} + r_{B})

JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Single correct option