Which one will show variable oxidation state?

(I) $\left[Kr\right]5s^1$                                 (II) $\left[Rn\right]5f^{14}6d^{1}7s^2$
(III)$\left[Ar\right]3d^{10}4s^{2}4p^5$                    (IV) $\left[Ar\right]3d^{6}4s^2$

If period number and group number of any representative element(s) are same then which of the following statement is incorrect regarding such type element(s) in their ground state?

(1) The possible value of principal quantum number is 2

(2) The possible value of azimuthal quantum number is zero

(3) The possible value of magnetic quantum number is 1

(4) The species could be paramagnetic

How does the energy gap between successive energy levels in an atom vary from low to high n values?

(1) All energy gaps are the same

(2) The energy gap decreases as  n increases

(3) The energy gap increases as  n  increases 

(4) The energy gap changes unpredictably as  n  increases

In alkaline earth metals, the properties, from the following, that will increase from Be to Ba are-

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

The incorrect order of ionic size among the following is :

(1)$\mathrm{ L}{a}^{3+}>G{d}^{3+}>E{u}^{3+}>L{u}^{3+}$           (2)${\mathrm{ V}}^{2+}>V^{3+}>V^{4+}>V^{5+}$

(3) $T{l}^{+}>I{n}^{+}>S{n}^{2+}>S{b}^{3+}$                (4)${\mathrm{ K}}^{+}>S{c}^{3+}>V^{5+}>M{n}^{7+}$

Aqueous solutions of two compounds $M_1-O-H and M_2-O-H$ are prepared in two different beakers. If, the electronegativity of $M_1=3.4 , M_2=1.2, O=3.5 and H=2.1,$ then the nature of two solutions will be respectively:

(a) acidic, basic             (b) acidic, acidic

(c) basic, acidic             (d) basic, basic

If the ionization enthalpy and negative electron gain enthalpy of an element are 275 and 86 kcal $mo{l}^{-1}$ respectively, then the electronegativity of the element on the Pauling scale is:

1. 2.8                                     

2. 0.0

3. 4.0                                     

4. 2.6

Consider the following ionisation reactions :

I.E. (kJ $mo{l}^{-1}$)

$A_{\left(g\right)}\to A_{\left(g\right)}^{+}+e^{-} , A_1$
$B_{\left(g\right)}^{+}\to B_{\left(g\right)}^{2+}+e^{-}, B_2$
$C_{\left(g\right)}^{+}\to C_{\left(g\right)}^{2+}+e^{-}, C_2$
$B_{\left(g\right)}\to B_{\left(g\right)}^{+}+e^{-}, B_1$
$C_{\left(g\right)}\to C_{\left(g\right)}^{+}+e^{-}, C_1$
$C_{\left(g\right)}^{2+}\to C_{\left(g\right)}^{3+}+e^{-}, C_3$

If monovalent positive ion of A, divalent positive ion of B and trivalent positive ion of C have zero electron. Then incorrect order of corresponding I.E. is :

(1) $C_3>C_2>B_2$                       

(2) $B_1>A_1>C_1$

(3) $C_3>C_2>B_2$                       

(4) $B_2>C_3>A_1$

The incorrect match among the following options is : 

1.$$ $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{5}4{\mathrm{s}}^1\to$ $4^{\mathrm{th}}$ $\mathrm{period},$ $6^{\mathrm{th}}$ $\mathrm{group}$

2. $$ $\left[\mathrm{Kr}\right]4{\mathrm{d}}^{10}\to$ $5^{\mathrm{th}}$ $\mathrm{period},$ ${12}^{\mathrm{th}}$ $\mathrm{group}$

3. $$ $\left[\mathrm{Rn}\right]6{\mathrm{d}}^{2}7{\mathrm{s}}^2\to$ $7^{\mathrm{th}}$ $\mathrm{period},$ $3^{\mathrm{th}}$ $\mathrm{group}$

4. $$ $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{14}5{\mathrm{d}}^{2}6{\mathrm{s}}^2\to$ $6^{\mathrm{th}}$ $\mathrm{period},$ $4^{\mathrm{th}}$ $\mathrm{group}$

Which of the following order is correct for the property mentioned in brackets?

$\left(a\right) S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$                 (Ionisation energy)

$\left(b\right) C<N<F<O$                              (2nd Ionisation energy)

$\left(c\right) B>Al>Ga>In>Tl$                     (Electronegativity)

$\left(d\right)N{a}^{+}>L{i}^{+}>M{g}^{2+}>B{e}^{2+}>A{l}^{3+}$    (Ionic radius)