The screening effect of 'd' electrons is:

1. Much less than s-electrons.

2. Much more than s-electrons.

3. Equal to s-electrons.

4. Equal to p-electrons.

Correct statement regarding transuranic elements is :

1. They have higher atomic number than uranium.

2. They are lighter than uranium.

3. They have lower atomic number than uranium.

4. They have same atomic number as uranium.

The correct  sequence of increasing order of density is:

1. Li < K< Na < Rb < Cs

2. Li < Na < K < Rb < Cs

3. Cs < Rb < K < Na < Li

4. K < Li < Na < Rb < Cs

General electronic configuration of outermost and penultimate shell of an atom is
(n - 1)s² (n - 1) p⁶ (n - 1)d^x ns². If n = 4 and x = 5, the number of proton in the nucleus is:

1. > 25

2. < 24

3. 25

4. 30

The maximum number of valence electrons possible for atoms in the second period of the periodic table is:

1. 18

2. 10

3. 8

4. 2

The element having atomic number 19, is:

1. an inert gas

2. a metal with oxidation number +1

3. a non-metal with oxidation number -3

4. a metal with oxidation number -3

Which of the following has the least density?

1. Na

2. Li

3. Mg

4. K

Eka aluminium and Eka silicon are now known as:

An element having the electronic configuration of its atom ns² np² should have similar properties to those of:

1. Sodium

2. Carbon

3. Magnesium

4. Oxygen

The order of basic character of given oxides is:

1. Na₂O > MgO > Al₂O₃ > CuO

2. MgO > Al₂O₃ > CuO > Na₂O

3. Al₂O₃ > MgO > CuO > Na₂O

4. CuO > Na₂O > MgO > Al₂O₃