MolSynapsequestion bank

MolSynapse / Question bank / Solid State / Cubic unit cells: packing efficiency and density

JEE Main levelSingle correct optionDifficulty 2 of 3ss028

In a cubic unit cell, atoms P occupy all 8 corners except one, atoms Q occupy the centres of all 6 faces and atoms R occupy the body centre. The simplest formula of the compound is

A $P X_{7} Q X_{6} R$
B $P X_{7} Q X_{24} R X_{8}$
C $PQ X_{3} R$
D $P X_{8} Q X_{6} R$

Answer: B

P:

7 \times \frac{1}{8} = \frac{7}{8}

; Q:

6 \times \frac{1}{2} = 3

; R:

1

. Ratio

\frac{7}{8} : 3 : 1 = 7 : 24 : 8

after multiplying by 8, so the formula is

P X_{7} Q X_{24} R X_{8}

.

Practice Solid State More on Cubic unit cells: packing efficiency and density

Previous questionNext question

More questions on Cubic unit cells: packing efficiency and density