Relation Between r and a

Q. In an FCC unit cell, what fraction of the edge is not covered by atoms?

1. 0.134
2. 0.293
3. 0.26
4. 0.32

Q.

A given metal crystallizes out with a cubic structure having edge length of 361 pm. If there are four metal atoms in one unit cell, what is the radius of one atom?

1. 108 pm

2. 40 pm

3. 127 pm

4. 80 pm

Q.

The edge length of a F.C.C. cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is

1. 288 pm

2. 398 pm

3. 618 pm

4. 144 pm

Q. Which of the following amine will give the carbylamine test?

1. 
2. 
3. 
4. 

Q.

Niobium crystallises in body - centred cubic structure. If density is $8.55gc{m}^{-3}$. Calculate atomic radius of niobium using its atomic mass 93 u.

Q.

If the radius of the octahedral void is r and radius of the atoms in close-packing is R, derive relation between nr and R.

Q.

CsBr crystal has bcc structure. It has an edge length of $4.3\stackrel{\circ }{A}$. The shortest interionic distance between $C{s}^{+}$ and $B{r}^{-}$ ions is

1. $4.30\stackrel{\circ }{A}$

2. $3.72\stackrel{\circ }{A}$

3. $7.44\stackrel{\circ }{A}$

4. $1.86\stackrel{\circ }{A}$

Q. Elements A and B crystallize in cubic structure where atoms A are at the corners of cube and B atoms are at the alternate faces. What is the formula of the compound? Here, what is the meaning of alternate faces?

Q. Copper crystallises in a structure of face centred cubic unit cell. The atomic radius of copper is $1.28A^{\circ }$. What is the edge length of a unit cell of copper?

1. $2.16A^{\circ }$
2. $4.15A^{\circ }$
3. $3.62A^{\circ }$
4. $3.94A^{\circ }$

Q.

Xenon crystallizes in the face-centred cubic lattice and the edge of the unit cell is 620 pm. What is the nearest neighbor distance and what is the radius of xenon atom?

1. 438pm

2. 240pm

3. 135pm

4. 98pm

Q.

A binary solid $\left(A^{+}{B}^{-}\right)$ has a rock salt structure. If the edge length is 400 pm and radius of cation is 75 pm, the radius of anion is

1. 100 pm

2. 125 pm

3. 250 pm

4. 325 pm

Q.

What will be the coordination number of Al in crystalline state of $AlC{l}_3$? ___

Q.

A metallic disc is being heated. Its area A (in $m^2$) at any time T (in second) is given by $A=5t^2+4t+8$. Calculate the rate of increase in area at $T=3s$

Q.

$CsCl$ crystallizes in B.C.C lattice. If ‘a’ is its edge length then which of the following expressions is correct?

1. $r_{Cs}+r_{C{l}^{-}}=\frac{\sqrt{3}}{2}a$
2. $r_{C{l}^{-}}+r_{Cs}=\sqrt{3}a$
3. $r_{Cs}+r_{C{l}^{-}}=3a$
4. $r_{Cs}+r_{C{l}^{-}}=\frac{3a}{2}$

Q. The length of the side of a unit cell for lithium is 351 pm, calculate its atomic radius. Lithium forms a body-centred cubic crystal.

1. 303.9 pm
2. 124.09 pm
3. 151.9 pm
4. 202.6 pm

Q. A substance AxBy crystallises in a FCC lattice. Atoms `A occupy each corner of the cube and atoms `B occupy the centres of each face of the cube. The correct composition of AxBy is

Q.

Gold (atomic radius = 0.144 nm) crystallises in a face-centred uinit cell. What is the length of a side of the cell ?

Q.

KCl crystallizes in the same type of lattice as does NACl. Given that $\frac{r_{N{a}^{+}}}{r_{C{l}^{-}}}=0.55$ and $\frac{r_{K^{+}}}{r_{C{l}^{-}}}=0.74$. Calculate the ratio of the side of the unit cell for KCl to that of NaCl.

1. 0.891

2. 0.414

3. 1.414

4. 1.123

Q. In FCC unit cell edge length is

1. $\frac{\sqrt{3}}{2}r$
2. $\frac{4}{\sqrt{3}}r$
3. $\frac{4}{\sqrt{2}}r$
4. $2r$

Q.

Edge length of a cubic unit cell is 400 pm. Its face diagonal would be

1. 600 pm

2. 200 pm

3. 566 pm

4. 692 pm

Q.

Cube of $-\frac{1}{2}$ is

1. $\frac{1}{8}$

2. $\frac{1}{16}$

3. $-\frac{1}{8}$

4. $-\frac{1}{16}$

Q. The edge length of a body-centre cubic unit cell is $390pm.$ If the radius of the cation is $150pm$, what is the radius of the anion?

1. $147.7pm$
2. $167.7pm$
3. $187.7pm$
4. $197.7pm$

Q. In the crystals of which of the following ionic compounds would you expect maximum distance between centers of cations and anions

1. LiF
2. CsF
3. CsI
4. LiI

Q. An element A (Atomic weight = 120) having bcc structure has unit edge length 400 pm. Identify the correct option(s). (Given: $N_A=6\times {10}^{23}$)

1. The density of solid element is $6.25g/c{m}^3$
2. There are $6\times {10}^{22}$ unit cells in 24 g of the solid element
3. The atomic radius is about $1.732\stackrel{\circ }{A}$
4. In 25 g of solid element, the volume occupied by atoms is nearly $2.72c{m}^3$ only

Q. Polonium adopts a cubic structure with an edge length of the cube being $0.336nm$. The distance between the polonium atoms which lie at the corners along the body diagonal is:

1. $0.336nm$
2. $0.291nm$
3. $0.582nm$
4. $0.481nm$

Q. Sodium metal crystallizes as a body centred cubic lattice with the cell edge 4.29 $\stackrel{\circ }{A}$. What is the radius of sodium atom

1. 1.857 x 10^-8
2. 2.371 x 10^-7
3. 3.817 x 10^-8
4. 9.312 x 10^-7

Q. Two ionic solids $AB$ and $CB$ crystallize in the same lattice. If $\frac{r_{A^{+}}}{r_{B^{-}}}$ and $\frac{r_{C^{+}}}{r_{B^{-}}}$ are $0.50$ and $0.70$, respectively, then the ratio of edge length of $AB$ and $CB$ is

1. 0.69
2. 0.78
3. 0.98
4. 0.88

Q.

A compound that gives positive iodoform test is:

1. 1-Pentanol

2. Pentanal

3. 3-Pentanone

4. 2-Pentanone

Q. Copper adopts fcc structure with edge length of unit cell equal to 0.361 nm. The value of $r_{metallic}$ :-

1. 0.128 nm
   
2. 0.091 nm
   
3. 0.180 nm
   
4. 0.64 nm

Q.

Body diagonal of a cube is 866 ppm. Its edge length would be

1. 600 pm

2. 500 pm

3. 1000 pm

4. 408 pm