Which ion is isoelectronic with Be²⁺?

1.	$H^{+}$	2.	$L{i}^{+}$
3.	$N{a}^{+}$	4.	$M{g}^{2+}$

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⁺

Match the name of elements given in list-I with the corresponding electronic configuration given in list-II and select the correct answer using the codes given below:

Codes :

Which of the following orders is correct for the given properties?

1. F > Cl > Br > I (Electron affinity)

2. I^-> I > I⁺ (Ionisation Energy)

3. I^-> I > I⁺ (Atomic/ionic radii)

4. I⁺⁷ > I⁺ > I⁺⁵ (Ionisation Energy)

Among ${\mathrm{P}}_2{\mathrm{O}}_5,<mspace\; width="1em"></mspace>{\mathrm{As}}_2{\mathrm{O}}_3,<mspace\; width="1em"></mspace>{\mathrm{Sb}}_2{\mathrm{O}}_3<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{Bi}}_2{\mathrm{O}}_3$, the most acidic oxide is:

1.  $P_2{O}_5$

2.  $A{s}_2{O}_3$

3.  $S{b}_2{O}_3$

4.  $B{i}_2{O}_3$

The first four ionization energy values of a metal are 191, 587, 872, and 5962 kcal/mol respectively. The number of valence electrons in the element is/are:

1.  1

2.  2

3.  3

4.  5

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

Which of the following properties of the alkaline earth metals increase from Be to Ba?

(i) Atomic radius       
(ii) Ionisation energy       
(iii) Nuclear charge

1. (i) and (ii)                                 

2. (i) and (iii)

3. (ii) and (iii)                               

4. (i), (ii) and (iii)

Which of the following orders of ionic radii is correctly represented?