The oxidation state that cerium (Ce) most commonly exhibits are:

1. +2, +3
2. +2, +4
3. +3, +4
4. +3, +5

The correct order of decreasing second ionization enthalpy of Ti(22), V(23), Cr (24) and Mn(25) is :

1.  Cr > Mn > V > Ti

2.  V > Mn > Cr > Ti

3.  Mn > Cr > Ti > V

4.  Ti > V > Cr > Mn

Electronic configuration of a transition element X in +3 oxidation state is [Ar] 3d⁵. What is its atomic number?

1. 25

2. 26

3. 27

4. 24

Which of the following statements is true? 

Based on the metallic radii provided, which transition element exhibits the highest density?

1. Fe 

2. Ti

3. Co

4. Cu

A compound that has coloure in solid state is:

1. \(Ag_2SO_4\)

2. \(CuF_2\)

3. \(ZnF_2\)

4. \(Cu_2Cl_2\)

On addition of small amount of KMnO₄, to concentrated H₂SO₄, a green oily compound is obtained which is highly explosive in nature. What is the compound ?
$1. {\mathrm{Mn}}_2{\mathrm{O}}_7$
$2. {\mathrm{MnO}}_2$
$3. {\mathrm{MnSO}}_4$
$4. {\mathrm{Mn}}_2{\mathrm{O}}_3$

The magnetic nature of elements depends on the presence of unpaired electrons. Which of the configuration of transition element will shows highest magnetic moment ?

$1. 3{\mathrm{d}}^7$

$$
$2. 3{\mathrm{d}}^5$

$$
$3. 3{\mathrm{d}}^8$

$$
$4. 3{\mathrm{d}}^2$

There are 14 elements in actinoid series. Which of the following elements does not belong to this series?

1. U

2. Np

3. Tm

4. Fm

The electronic configuration of gadolinium (atomic number of 64) is:

1. $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{3}5{\mathrm{d}}^{5}6{\mathrm{s}}^2$

2. $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{7}5{\mathrm{d}}^{2}6{\mathrm{s}}^1$

3. $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{7}5{\mathrm{d}}^{1}6{\mathrm{s}}^2$

4. $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{8}5{\mathrm{d}}^{6}6{\mathrm{s}}^2$