Atomic Radius

Q. The percentage packing efficiency of the two dimensional hcp arrangement of sphere for unit cell ABCDEF shown below is:

1. 90.64%
2. 74.05%
3. 68.02%
4. 78.54%

Q. The nucleophilicity order of halogens in polar protic solvent is :

1. $F^{-}>C{l}^{-}>B{r}^{-}>I^{-}$
2. $F^{-}>I^{-}>B{r}^{-}>C{l}^{-}$
3. $F^{-}<C{l}^{-}<B{r}^{-}<I^{-}$
4. $C{l}^{-}>F^{-}>B{r}^{-}>I^{-}$

Q. The ratio of radii of first orbit of $H$, $H{e}^{+}$ and $L{i}^{2+}$ is:

1. 1 : 2 : 3
2. 6 : 3 : 2
3. 1 : 4 : 9
4. 9 : 4 : 1

Q. The electronic configuration of $Cu\left(II\right)$ is $3d^9$, whereas that of $Cu\left(I\right)$ is $3d^{10}.$ Which of the following is correct?

1. $Cu\left(II\right)$ is more stable
2. $Cu\left(I\right)\text{and}Cu\left(II\right)$ are equally stable
3. Stability of $Cu\left(I\right)$ and $Cu\left(II\right)$ depends on nature of copper salts
4. $Cu\left(II\right)$ is less stable

Q. The effective nuclear charge across the period (from left to right)

1. First increases and then decreases
2. Increases
3. Decreases
4. First decreases and then increases

Q.

The correct order of decreasing ionic radii among the following isoelectronic species is:

1. $C{l}^{-}>C{a}^{2+}>S^{2-}>K^{+}$
2. $C{l}^{-}>S^{2-}>C{a}^{2+}>K^{+}$
3. $S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$
4. $K^{+}>S^{2-}>C{a}^{2+}>C{l}^{-}$

Q. Buna-N synthetic rubber is a copolymer of

1. 
2. 
3. 
4. 

Q. When does a gas deviate the most from its ideal behaviour?

1. At low pressure and low temperature
2. At low pressure and high temperature
3. At high pressure and low temperature
4. At high pressure and high temperature

Q.

Describe the theory associated with the radius of an atom as it (a)gains an electron
(b)loses an electron

Q. Which of the following statement(s) is true regarding triangular voids?

1. Triangular voids are formed in 1-D close packing
2. Coordination number of triangular void is 6
3. $\text{Maximum radius of triangular void}=0.155\times \text{radius of sphere}$
4. $\text{Maximum radius of triangular void}=0.225\times \text{radius of sphere}$

Q. Among the following oxides, which has the maximum lattice energy?

1. $CaO$
2. $SrO$
3. $BaO$
4. $MgO$

Q. In van der Waals equation of state of gas laws, the constant $b$ is a measure of

1. Intermolecular collisions per unit volume
2. Intermolecular attraction
3. Volume of the molecules
4. Pressure exerted by the gas molecules on the surface

Q. Among the following species, which has the maximum hydration energy?

1. $O{H}^{-}$
2. $N{H}_4^{+}$
3. $F^{-}$
4. $H^{+}$

Q.

What does atomic radius and ionic radius really mean to you?

Q. Assertion: Compressibility factor for hydrogen varies with pressure with positive slope at all pressure.
Reason: Even at low pressure, repulsive forces dominate for hydrogen gas.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion
3. Assertion is true but reason is false
4. Both assertion and reason are false

Q.

Choose the corect order of atomic radii of fluorine and neon (in pm ) out of the options given below and justify your answer.
(a) 72, 160 (b) 160, 160 (c) 72, 7 (d) 160, 72

Q. Consider the following table:

Gas	$a\left(kPad{m}^{6}mo{l}^{-2}\right)$	$b\left(d{m}^{3}mo{l}^{-1}\right)$
A	642.32	0.05196
B	155.21	0.04136
C	431.91	0.05196
D	155.21	0.4382

a and b are vander waals constant. The correct statement about the gases is:

1. Gas C will ocupy lesser volume than gas A; gas B will be lesser compressible than gas D
2. Gas C will occupy more volume than gas A; gas B will be lesser compressible than gas D
3. Gas C will occupy more volume than gas A; gas B will be more compressible than gas D
4. Gas C will occupy lesser volume than gas A; gas B will be more compressible than gas D

Q. The value of lattice energy is affected by

1. Size and charge of ions
2. Mass of ions
3. Charge of ions only
4. Size of ions only

Q. The correct decreasing order of atomic size of the following species is:
$K^{+},C{l}^{-},S^{2-},C{a}^{2+}$

1. $C{a}^{2+}>K^{+}>C{l}^{-}>S^{2-}$
2. $S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$
3. $S^{2-}>C{l}^{-}>C{a}^{2+}>K^{+}$
4. $K^{+}>C{a}^{2+}>C{l}^{-}>S^{2-}$

Q. The ′f′ orbitals are half and completely filled, respectively in lanthanide ions
[Given: Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]

Q. Find the correct order of the ionic radius of following isoelectronic species.

1. $C{a}^{2+}<K^{+}<S^{2-}<C{l}^{-}$
2. $C{a}^{2+}<K^{+}<C{l}^{-}<S^{2-}$
3. $K^{+}<C{a}^{2+}<S^{2-}<C{l}^{-}$
4. $K^{+}<C{a}^{2+}<C{l}^{-}<S^{2-}$

Q. Answer the following questions

A) Which element of the first transition series has highest second ionisation enthalpy?

B) Which element of the first transition series has the highest third ionisation enthalpy?

C) Which element of the first transition series has lowest enthalpy of atomisation?

Q. What is the difference between the terms orbit and orbital?

Q. In which of the following pairs, the difference between the covalent radii of two metals is maximum?

1. $K,Ca$
2. $Cr,Mn$
3. $Mn,Fe$
4. $Co,Ni$

Q. Aluminium has a diagonal relationship with:

1. $Li$
2. $Si$
3. $Be$
4. $B$

Q. There are three cubic unit cells $A,B$ and $C$. $A$ is $FCC$ and all of its tetrahedral voids are also occupied. $B$ is also $FCC$ and all of its octahedral voids are also occupied. $C$ is simple cubic and all of its cubic voids are also occupied. If voids in all unit cells are occupied by the spheres exactly at their limiting radius, the order of packing efficiency would be:

1. $A<B<C$
2. $C<A<B$
3. $C<B<A$
4. $A<C<B$

Q. For the given 2-D unit cell in hexagonal close packing, the packing fraction will be:

1. 0.521
2. 0.907
3. 0.093
4. 0.745

Q. Which of the alkaline earth metal halides given below is essentially covalent in nature ?

1. $BeC{l}_2$
2. $MgC{l}_2$
3. $SrC{l}_2$
4. $CaC{l}_2$

Q. The covalent and vander Waals radii of chlorine respectively are

1. and
2. and
3. and
4. and

Q. Which of the following statement is correct?

1. For potassium, the atomic radius < ionic radius but for bromine atomic radius> ionic radius
2. For potassium and bromine both, atomic radius > ionic radius
3. For potassium and bromine both, atomic radius < ionic radius
4. For potassium, the atomic radius > ionic radius but for bromine atomic radius < ionic radius