The species Ar, K⁺ and Ca²⁺ contain the same number of electrons. In which order do their radii increase?
1.  Ar < K⁺ < Ca²⁺
2. Ca²⁺ < Ar < K⁺
3. Ca²⁺ < K⁺ < Ar
4. K⁺ < Ar < Ca²⁺

The correct order of ionic radii is:

1. $H^{-}>H^{+}>H$ $$
2. $N{a}^{+}>F^{-}>O^{2-}$
3. $F^{-}>O^{2-}>N{a}^{+}$
4. $N^{3-}>M{g}^{2+}>A{l}^{3+}$

The correct order of increasing electron affinity for the elements, O, S, F and Cl is:

Amongst the elements with the following electronic configurations, which one of them may have the highest ionisation energy?

1. $\left[Ne\right]$ $3s^2$ $3p^3$

2. $\left[Ne\right]$ $3s^2$ $3p^2$

3. $\left[Ar\right]$ $3d^{10}$ $4s^2$ $4p^3$

4. $\left[Ne\right]$ $3s^2$ $3p^1$

The correct order of increasing bond angles in the following triatomic species is:

1. ${\mathrm{NO}}_2^{-}$ $<$ ${\mathrm{NO}}_2^{+}$ $<$ ${\mathrm{NO}}_2$

2. ${\mathrm{NO}}_2^{-}$ $<$ ${\mathrm{NO}}_2$ $<$ ${\mathrm{NO}}_2^{+}$

3. ${\mathrm{NO}}_2^{+}$ $<$ ${\mathrm{NO}}_2$ $<$ ${\mathrm{NO}}_2^{-}$

4. ${\mathrm{NO}}_2^{+}$ $<$ ${\mathrm{NO}}_2^{-}$ $<$ ${\mathrm{NO}}_2$

Among the following, the most characteristic oxidation states for lead and tin are, respectively:

1. +4, +2

2. +2, +4

3. +4, +4

4. +2, +2

A configuration with the lowest ionization enthalpy among the following is:
1. \(1 s^2 2 s^2 2 p^5\)$\mathrm{}$
2. \(1 s^2 2 s^2 2 p^3\)
3. \(1 s^2 2 s^2 2 p^6 3 s^1\)
4. \(1 s^2 2 s^2 2 p^6\)

Which one of the following orders is not in accordance with the property stated against?

1. $F_2>C{l}_2>B{r}_2>I_2$ $:$ $Oxidi\sin g$ $power$

2. $Hl>HBr>HCl>HF$ $:$ $Acidic$ $property$ $in$ $water$

3. $F_2>C{l}_2>B{r}_2>I_2$ $:$ $Electronegativity$

4. $F_2>C{l}_2>B{r}_2>I_2$ $:$ $Bond$ $dissociation$ $energy$