The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of Na⁺ will be -

1. – 10.2 eV

2. + 2.55 eV

3. – 2.55 eV

4. – 5.1 eV

The correct sequence of increasing the basic nature of the following oxides is: 

1. ${\mathrm{Al}}_2{\mathrm{O}}_3<\mathrm{MgO}<{\mathrm{Na}}_2\mathrm{O}<{\mathrm{K}}_2\mathrm{O}$

2. $\mathrm{MgO}<{\mathrm{K}}_2\mathrm{O}<{\mathrm{Al}}_2{\mathrm{O}}_3<{\mathrm{Na}}_2\mathrm{O}$

3. ${\mathrm{Na}}_2\mathrm{O}<{\mathrm{K}}_2\mathrm{O}<\mathrm{MgO}<{\mathrm{Al}}_2{\mathrm{O}}_3$

4. ${\mathrm{K}}_2\mathrm{O}<{\mathrm{Na}}_2\mathrm{O}<{\mathrm{Al}}_2{\mathrm{O}}_3<\mathrm{MgO}$

The ionic radii (in Å) of ${\mathrm{N}}^{3-},<mspace\; width="1em"></mspace>{\mathrm{O}}^{2-}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{F}}^{-}$ are respectively :

1. 1.36, 1.40 and 1.71

2. 1.36, 1.71 and 1.40

3. 1.71, 1.40 and 1.36

4. 1.71, 1.36 and 1.40

The set representing the correct order of ionic radius is :

1. Li⁺> Be²⁺ > Na⁺> Mg²⁺

2. Na⁺> Li⁺> Mg²⁺ > Be²⁺

3. Li⁺> Na⁺> Mg²⁺ > Be²⁺

4. Mg²⁺ > Be²⁺ > Li⁺> Na⁺

The correct representation of the first ionization enthalpy for
Ca, Ba, S, Se, and Ar in increasing order, among the following, is:

1. Ba < Ca < Se < S < Ar

2. Ca < Ba < S < Se < Ar

3. Ca < S < Ba < Se < Ar

4. S < Se < Ca < Ba < Ar

The correct order of electron gain enthalpy is:

1. S > Se > Te > O

2. Te > Se > S > O

3. O > S > Se > Te

4. S > O > Se > Te

The set that contains atomic numbers of only transition elements is:

1. 21, 32, 53, 64

2. 9, 17, 34, 38

3. 21, 25, 42, 72

4. 37, 42, 50, 64

Consider the following compounds:

BeO, BaO, Be(OH)₂, Sr(OH)₂

The amphoteric compound(s) are:

Consider the elements Mg, Al, S, P, and Si, the correct increasing order of their first ionization enthalpy is:

1. Mg < Al < Si < S < P

2. Al < Mg < Si < S < P

3. Mg < Al < Si < P < S

4. Al < Mg < S < Si < P