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 the decreasing ionic radii among the following isoelectronic species is:

1. $C{a}^{2+}>K^{+}>S^{2-}>C{l}^{-}$

2. $C{l}^{-}>S^{2-}>C{a}^{2+}>K^{+}$

3. $S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$

4. $K^{+}>C{a}^{2+}>C{l}^{-}>S^{2-}$

Among the elements Ca, Mg, P and Cl, the correct order of increasing atomic radii is:
1. Cl < P < Mg < Ca
2. P < Cl < Ca < Mg
3. Ca < Mg < P < Cl
4. Mg < Ca < Cl < P

Identify the correct order of the size of the following:

1. $C{a}^{2+}<K^{+}<Ar<S^{2-}<C{l}^{-}$

2. $C{a}^{2+}<K^{+}<Ar<C{l}^{-}<S^{2-}$

3. $Ar<C{a}^{2+}<K^{+}<C{l}^{-}<S^{2-}$

4. $C{a}^{2+}<A{r}^{+}<K^{+}<C{l}^{-}<S^{2-}$