# NEET Chemistry The Solid State Questions Solved

BOARD

Silver crystallises with  face-centred cubic unit cells. Each side of the unit cell has a length of 409 pm. What is the radius of an atom of silver? (Assume that each face atom is touching the four corner atoms.)

Given : a = 409 pm     r = ?

For fcc unit cell, the formula is

r = $\frac{a}{2\sqrt{2}}$

or r = $\frac{409}{2\sqrt{2}}$ = $\frac{409}{2×1.414}$ = $\frac{409}{2.828}$

$\therefore$ r = 144.62

$\therefore$ Radius of an atom of silver = 144.62 pm

Difficulty Level:

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