The correct order of 3rd ionisation potential of Na, Mg, Al and Si is

1. Si > Al > Mg > Na

2. Mg > Si > Al > Na

3. Mg > Na > Si > Al

4. Mg > Na > Al > Si

Identify the wrong statement in the following:

(1) Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius

(2) Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius

(3) Atomic radius of the elements increases as one moves down the first group of the Periodic Table

(4) Atomic radius of the elements decreases as one moves across from left to right in the 2nd period of the Periodic Table

The ionisation energy will be maximum for the process:

(1) $Ba\to B{a}^{2+}$

(2) $Be\to B{e}^{2+}$

(3) $Cs\to C{s}^{+}$

(4) $Li\to L{i}^{+}$

Which species among the following exhibits the highest electron affinity?

1. F^–
2. O^–
3. O
4. Na

Isoelectronic pair, among the following, is : 

1. ${\mathrm{ClO}}_2^{-}, {\mathrm{ClF}}_2^{+}$

2. ${\mathrm{IF}}_2^{-}, {\mathrm{I}}_3^{-}$

3. ${\mathrm{Cl}}_2\mathrm{O}, {\mathrm{ICl}}_2^{-}$

4. ${\mathrm{ICl}}_2^{-}, {\mathrm{ClO}}_2$

The group of metals having positive value of electron gain enthalpy is :-

Percentage ionic character, if electronegativity value of X=2.1 & Y=3.0, is :-

The correctly matched option is:-

1. ${\mathrm{Fe}}^{+3}>{\mathrm{Fe}}^{+2}$ $>$ ${\mathrm{Fe}}^{+}$  : Order of atomic radius 

2. O > C > B > N   : Order of ionisation energy 

3. ${\mathrm{O}}^{-2}$ $<{\mathrm{O}}^{-}$ $<\mathrm{O}$ $<{\mathrm{O}}^{+}$ :  Increasing order of Z_eff

4. O < N < F < Ne  :  Order of electron affinity

The pair that has both members from the same period of the Periodic Table is 

Element of the third period that is expected to exhibit positive electron gain enthalpy is: