Classification of Elements and Periodicity in Properties MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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161.
The correct order of decreasing electronegativity values among the elements (i) - beryllium, (ii) - oxygen, (iii) - nitrogen and (iv) - magnesium is
A
(ii) > (iii) > (i) > (iv)
B
(iii) > (iv) > (ii) > (i)
C
(i) > (ii) > (iii) > (iv)
D
(i) > (ii) > (iv) > (iii)
Answer :
(ii) > (iii) > (i) > (iv)
Electronegativity values of given elements are as follows :
$$\eqalign{
& Be - 1.5\left( {\text{i}} \right)\,\,\,\,\,\,\,\,\,\,\,\,Mg - 1.2\left( {{\text{iv}}} \right) \cr
& O - 3.5\left( {{\text{ii}}} \right)\,\,\,\,\,\,\,\,\,\,\,\,N - 3.0\left( {{\text{iii}}} \right) \cr
& {\text{i}}{\text{.e}}{\text{.}}\,\,\left( {{\text{ii}}} \right){\text{ > }}\left( {{\text{iii}}} \right){\text{ > }}\left( {\text{i}} \right){\text{ > }}\left( {{\text{iv}}} \right) \cr} $$
162.
Which one of the following groups represents a collection of isoelectronic species? $$\left( {{\text{At}}{\text{.}}\,{\text{nos}}.:Cs - 55,Br - 35} \right)$$
A
$$N{a^ + },C{a^{2 + }},M{g^{2 + }}$$
B
$${N^{3 - }},{F^ - },N{a^ + }$$
C
$$Be,A{l^{3 + }},C{l^ - }$$
D
$$C{a^{2 + }},C{s^ + },Br$$
Answer :
$${N^{3 - }},{F^ - },N{a^ + }$$
All the three species $${N^{3 - }},{F^ - },N{a^ + }$$ have the same number of electrons (10) hence are called isoelectronic species.
163.
Match the columns I, II and III and mark the appropriate choice.
Column I
Column II
Column III
a.
Bromine
1.
Noble metal
p.
Amalgam
b.
Gold
2.
Crystalline non-metal
q.
$$4{s^2}\,4{p^5}$$
c.
Mercury
3.
Liquid non-metal
r.
Transition metal
d.
Iodine
4.
Liquid metal
s.
Violet
A
a - 3, q; b - 1, r; c - 4, p; d - 2, s
B
a - 2, p, b - 1, s; c - 3, q; d - 4, r
C
a - 1, s; b - 2, p; c - 4, r; d - 3, q
D
a - iv, r; b - 3, q; c - 2, s; d - 1, p
Answer :
a - 3, q; b - 1, r; c - 4, p; d - 2, s
No explanation is given for this question. Let's discuss the answer together.
164.
The chemistry of lithium is very similar to that of magnesium even though they are placed in different groups. Its reason is :
A
Both are found together in nature
B
Both have nearly the same size
C
Both have similar electronic configuration
D
The ratio of their charge and size ( i.e. charge density ) is nearly the same
Answer :
The ratio of their charge and size ( i.e. charge density ) is nearly the same
Due to diagonal relationship.
165.
Consider the following ionization enthalpies of two elements $$'A'$$ and $$'B'.$$
Element
Ionization
enthalpy $$\left( {kJ/mol} \right)$$
1st
2nd
3rd
A
899
1757
14847
B
737
1450
7731
Which of the following statements is correct ?
A
Both $$'A'$$ and $$'B'$$ belong to group - 1 where $$'B'$$ comes below $$'A'.$$
B
Both $$'A'$$ and $$'B'$$ belong to group - 1 where $$'A'$$ comes below $$'B'.$$
C
Both $$'A'$$ and $$'B'$$ belong to group - 2 where $$'B'$$ comes below $$'A'.$$
D
Both $$'A'$$ and $$'B'$$ belong to group - 2 where $$'A'$$ comes below $$'B'.$$
Answer :
Both $$'A'$$ and $$'B'$$ belong to group - 2 where $$'B'$$ comes below $$'A'.$$
Generally, the ionization enthalpies or energy increases from left to right in a period and decreases from top to bottom in a group. Several factor such as atomic radius, nuclear charge, shielding effect are responsible for change of ionization enthalpies.
Here, Ist ionization enthalpy of $$A$$ and $$B$$ is greater than group $$I\left( {Li = 520\,kJmo{l^{ - 1}}\,{\text{to}}\,Cs = 374\,kJ\,mo{l^{ - 1}}} \right),$$ which means element $$A$$ and $$B$$ belong to group –2 and all three given ionization enthalpy values are less for element $$B$$ means $$B$$ will come below $$A.$$
166.
Few values of enthalpies are given below :
$$\eqalign{
& O = - 141\,kJ\,mo{l^{ - 1}} \cr
& F = - 328\,kJ\,mo{l^{ - 1}} \cr
& S = - 200\,kJ\,mo{l^{ - 1}} \cr
& Cl = - 349\,kJ\,mo{l^{ - 1}} \cr} $$
What do these values show?
A
Ionisation enthalpy
B
Bond enthalpy
C
Electron gain enthalpy
D
Hydration enthalpy
Answer :
Electron gain enthalpy
Negative value of electron gain enthalpy of $$S$$ is more than that of oxygen and for $$Cl$$ it is more than that of fluorine.
167.
There are many elements in the periodic table which exhibit variable valency. This is a particular characteristic of
A
representative elements
B
transition elements
C
noble gases
D
non-metals
Answer :
transition elements
Transition elements show variable valency due to the presence of vacant $$d$$ - orbitals.
168.
Match the column I with column II and mark the appropriate choice.
Column I (Atomic number)
Column II
(Period)
(Group)
a.
14
1.
3
14
b.
53
2.
5
2
c.
38
3
6
10
d.
78
4
5
17
A
a - 2, b - 4, c - 3, d - 1
B
a - 1, b - 4, c - 2, d - 3
C
a - 3, b - 2, c - 1, d - 4
D
a - 2, b - 1, c - 3, d - 4
Answer :
a - 1, b - 4, c - 2, d - 3
No explanation is given for this question. Let's discuss the answer together.
169.
The electronic configuration of few elements is given below. Mark the statement which is not correct about these elements.
$$\eqalign{
& \left( {\text{i}} \right)1{s^2}2{s^2}2{p^6}3{s^1} \cr
& \left( {{\text{ii}}} \right)1{s^2}2{s^2}2{p^5} \cr
& \left( {{\text{iii}}} \right)1{s^2}2{s^2}2{p^6} \cr
& \left( {{\text{iv}}} \right)1{s^2}2{s^2}2{p^3} \cr} $$
A
(i) is an alkali metal.
B
(iii) is a noble metal.
C
(i) and (ii) form ionic compounds.
D
(iv) has high ionisation enthalpy.
Answer :
(iii) is a noble metal.
Element having configuration $$1{s^2}2{s^2}2{p^6}$$ is a noble gas.
170.
Electronic configurations of few elements are given below. Mark the incorrect match.
A
$$1{s^2}2{s^2}2{p^5} $$ - Most electronegative element
B
$$1{s^2}2{s^2}2{p^3} $$ - An element belonging to match.
3rd period and 5th group
C
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^8}4{s^2} $$ - A $$d$$ - block element
D
$$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6} $$ - An element from 18th group
Answer :
$$1{s^2}2{s^2}2{p^3} $$ - An element belonging to match.
3rd period and 5th group