This chapter is currently out of syllabus
1
JEE Main 2023 (Online) 1st February Evening Shift
Numerical
+4
-1
Out of Syllabus

A metal M crystallizes into two lattices :- face centred cubic (fcc) and body centred cubic (bcc) with unit cell edge length of $$2.0$$ and $$2.5\,\mathop A\limits^o$$ respectively. The ratio of densities of lattices fcc to bcc for the metal M is ____________. (Nearest integer)

2
JEE Main 2023 (Online) 30th January Evening Shift
Numerical
+4
-1
Out of Syllabus
Iron oxide FeO, crystallises in a cubic lattice with a unit cell edge length of 5.0 Å. If density of the $\mathrm{FeO}$ in the crystal is $4.0 \mathrm{~g} \mathrm{~cm}^{-3}$, then the number of $\mathrm{FeO}$ units present per unit cell is __________. (Nearest integer)

Given: Molar mass of $\mathrm{Fe}$ and $\mathrm{O}$ is 56 and $16 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively. $\mathrm{N}_{\mathrm{A}}=6.0 \times 10^{23} \mathrm{~mol}^{-1}$
3
JEE Main 2023 (Online) 29th January Evening Shift
Numerical
+4
-1
Out of Syllabus

A metal M forms hexagonal close-packed structure. The total number of voids in 0.02 mol of it is _________ $$\times$$ $$10^{21}$$ (Nearest integer).

(Given $$\mathrm{N_A=6.02\times10^{23}}$$)

4
JEE Main 2022 (Online) 29th July Morning Shift
Numerical
+4
-1
Out of Syllabus

Ionic radii of cation $$\mathrm{A}^{+}$$ and anion $$\mathrm{B}^{-}$$ are 102 and $$181 \,\mathrm{pm}$$ respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for $$\mathrm{B}^{-}$$. $$\mathrm{A}^{+}$$ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is __________ pm. (Nearest Integer)