JEE Main 2020 — Solid State Question with Solution
From: JEE Main 2020 (Online) 3rd September Morning Slot
Question
An element with molar mass 2.7 10-2 kg mol-1 forms a cubic unit cell with edge length 405 pm. If its
density is 2.7 103
kg m-3, the radius of the element is approximately ______ 10-12 m (to the
nearest integer).
Enter your answer
Show full solutionCorrect answer: 143
Correct answer
143
Step-by-step explanation
Molar mass of an element (M) = 27 gm mol–1
Edge length of a cubic unit cell (a) = 405 pm = 4.05 × 10–8 cm
density of the element (d) = 2.7 gm/cc
d =
2.7 =
Z = 4
The element has fcc unit cell
a = 4r
r =
= 143 pm
= 143 × 10–12 m
Edge length of a cubic unit cell (a) = 405 pm = 4.05 × 10–8 cm
density of the element (d) = 2.7 gm/cc
d =
2.7 =
Z = 4
The element has fcc unit cell
a = 4r
r =
= 143 pm
= 143 × 10–12 m
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