Which pair of elements is chemically most similar?

1. Na, Al

2. Cu, S

3. Ti, Zr

4. Zr, Hf

In the transition elements, the incoming electron occupies (n-1)d sublevel in preference to:

1. np

2. ns

3. (n-1)d

4. (n+1)s

The electronegativity of elements from group 1 to group 17 :

1. Decreases

2. Increases

3. Remains constant

4. All of the above

The electronic configuration of the most electropositive element is :

1. [He]2s¹

2. [Xe]6s¹

3. [He]2s²

4. [Xe]6s²

Which one of the following is an amphoteric oxide?

1. SO₂

2. B₂O₃

3. ZnO

4. Na₂O

Transition elements exhibit variable oxidation states because they release electrons from the following orbits:

1. ns and np orbits

2. (n-1)d and ns orbits

3. (n-1)d orbits

4. ns orbits

Elements of group IB  is called as:

Element that has the greatest tendency to lose an electron is :

The outer electronic configuration of Gd (Atomic no. 64) is:

1. 4f³ 5d⁵6d²

2. 4f⁸ 5d¹⁰6d²

3. 4f⁴ 5d⁴6d²

4. 4f⁷ 5d¹6s²

The radius of La³⁺ (at. no. 57) is 1.06 $\stackrel{°}{\mathrm{A}}$ The radius of Lu³⁺ (at.no. 71) might be:

1. 1.06  $\stackrel{°}{\mathrm{A}}$

2. 0.85  $\stackrel{°}{\mathrm{A}}$

3. 1.60  $\stackrel{°}{\mathrm{A}}$

4. 1.40  $\stackrel{°}{\mathrm{A}}$