Find the main reason responsible for actinide contraction.
1. Poor shielding by the 5f subshell
2. Extraordinary decrement in Z_eff
3. Both (1) and (2)
4. Strong shielding by the 5f subshell

From the following, which is the most basic hydroxide?

1. Ce(OH)₃

2. Lu(OH)₃

3. Yb(OH)₃

4. Tb(OH)₃

Which is colorless in water?

1. Ti³⁺

2. V³⁺

3. Cr³⁺

4. Sc³⁺

CrO₄^2- and MnO₄^- are strong yellow and intense purple  respectively in aqueous solution The darkening of colour is due to

1. charge transfer

2. d-d transition

3. half-filled d-sub shells

4. increasing number of unpaired electron

In the dichromate ion Cr₂O₇^2-,

1. 4 Cr-O bonds are equivalent

2. 6 Cr-O bonds are equivalent

3. All Cr-O bonds are equivalent

4. None of Cr-O bonds are equivalent

The electronic configuration of a transition element X in +3 Oxidation state is [Ar]3d⁵.

The atomic number of X is :

1. 25

2. 26

3. 27

4. 24

Magnetic moment of K₃[Fe(CN)₅(H₂O)] is

1. 0

2. 4.92

3. 3.87

4. 2.83

Which of the following lanthanoids is radioactive?

1. Promethium

2. Europium

3. Plutonium

4. Neptunium

A pair of ions having similar magnetic moments is:

1. Ti³⁺,V³⁺

2. Cr³⁺,Mn²⁺

3. Mn²⁺,Fe³⁺

4. Fe²⁺,Mn²⁺

Basic oxide amongst the following is:

1. CrO

2. Cr₂O₃

3. CrO₃

4. Cr₂O₄