Periodic Table & Periodicity Questions — JEE Chemistry

Q1

Chlorides of which metal are soluble in organic solvents :

A K

B Be

C Ca

D Mg

Correct Answer

Option B

Solution

\mathrm{BeCl_2}

is a covalent molecule So, it is soluble in organic solvents, rest are ionic compounds.

Q2

The correct order of the atomic radii of C, Cs, Al, and S is :

A S < C < Al < Cs

B S < C < Cs < Al

C C < S < Al < Cs

D C < S < Cs < Al

Correct Answer

Option C

Solution

Atomic radii increase by moving down the group and decrease across a period.

Hence, the correct order of atomic radii is : C < S < Al < Cs.

Q3

The electronegativity of aluminium is similar to :

A Beryllium

B Carbon

C Boron

D Lithium

Correct Answer

Option A

Solution

E.N. of Al = (1.5) $\cong$ Be (1.5)

Q4

Which of the following on thermal decomposition yields a basic as well as an acidic oxide?

A NaNO3

B KClO3

C CaCO3

D NH4NO3

Correct Answer

Option C

Solution

Calcium carbonate on thermal decomposition gives

CaO

(Basic oxide) and

C{O_2}

(Acidic oxide)

CaC{O_3}\overset{\Delta}\longrightarrow \mathop {\,\,\,\,\,CaO\,\,\,\,\,}\limits_{Basic\,\,oxide} + \,\,\mathop {\,\,\,\,C{O_2} \uparrow }\limits_{Acidic\,\,oxide}

Q5

The structures of beryllium chloride in the solid state and vapour, phase, respectively,are :

A chain and chain

B dimeric and chain

C chain and dimeric

D dimeric and dimeric

Correct Answer

Option C

Solution

BeCl2 in vapour phase exist as dimer [(BeCl2)2] (below 1200 K temperature).

BeCl2 in solid state has chain structure[(BeCl2)n].

Q6

Arrange the following in the decreasing order of their covalent character : (A) LiCl (B) NaCl (C) KCl (D) CsCl Choose the most appropriate answer from the options given below :

A (A) > (C) > (B) > (D)

B (B) > (A) > (C) > (D)

C (A) > (B) > (C) > (D)

D (A) > (B) > (D) > (C)

Correct Answer

Option C

Solution

Covalent character $\propto$ polarising power of cation Correct decreasing order of covalent character LiCl > NaCl > KCl > CsCl

Q7

The incorrect relationship in the following pairs in relation to ionisation enthalpies is :

A

\mathrm{Mn}^{2+}<\mathrm{Fe}^{2+}

B

\mathrm{Mn}^{+}<\mathrm{Mn}^{2+}

C

\mathrm{Mn}^{+}<\mathrm{Cr}^{+}

D

\mathrm{Fe}^{2+}<\mathrm{Fe}^{3+}

Correct Answer

Option A

Solution

\mathrm{Mn}^{2+}:[\mathrm{Ar}] 3 \mathrm{~d}^5

Half filled stability More 1E than $\mathrm{Fe}^{2+}$

\mathrm{Fe}^{2+}:[\mathrm{Ar}] 3 \mathrm{~d}^6

Q8

The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively :

A

\mathrm{B} ~\&~ \mathrm{Tl}

B

\mathrm{Tl} ~\& ~\mathrm{~B}

C

B ~\& ~\operatorname{In}

D

B ~\& ~G a

Correct Answer

Option C

Solution

\begin{aligned} &\text{ IE order }\\ &\mathrm{B}>\mathrm{T} \ell>\mathrm{Ga}>\mathrm{Al}>\mathrm{In} \end{aligned}

Q9

The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is :

A Cu

B Cr

C Ag

D Ca

Correct Answer

Option D

Solution

On electrolysis of aqueous solution of

s

-block elements

{H_2}

gas discharge at cathode. At cathode:

{H_2}O + {e^ - } \to {1 \over 2}{H_2} + O{H^ - }

Q10

The correct sequence of thermal stability of the following carbonates is :

A BaCO3 < SrCO3 < CaCO3 < MgCO3

B MgCO3 < CaCO3 < SrCO3 < BaCO3

C BaCO3 < CaCO3 < SrCO3 < MgCO3

D MgCO3 < SrCO3 < CaCO3 < BaCO3

Correct Answer

Option B

Solution

Stability of alkaline earth metal carbonates increases down the group as size of cation increases ans polarization decreases down the group : MgCO3 < CaCO3 < SrCO3 < BaCO3