Classification of Elements and Periodicity in Properties MCQ Questions & Answers in Inorganic Chemistry | Chemistry
Learn Classification of Elements and Periodicity in Properties MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
21.
The element having greatest difference between its first and second ionization energies, is:
A
$$Ca$$
B
$$Sc$$
C
$$Ba$$
D
$$K$$
Answer :
$$K$$
Alkali metals have high difference in the first and second ionisation energy as they achieve stable noble gas configuration after first ionisation.
22.
The electronic states $$X$$ and $$Y$$ of an atom are depicted below :
$$\eqalign{
& X:1{s^2}2{s^2}2{p^6}3{s^1} \cr
& Y:1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^1} \cr} $$
Which of the following statements is not correct?
A
$$X$$ represents an alkali metal.
B
More energy is required to remove an electron from $$X$$ than from $$Y.$$
C
$$Y$$ represents ground state of the element.
D
Less energy is required to remove an electron from $$X$$ than from $$Y.$$
Answer :
Less energy is required to remove an electron from $$X$$ than from $$Y.$$
Due to small size of atom $$X\left( {n = 3} \right)$$ than $$Y\left( {n = 4} \right),$$ the electron present in $$3{s^1}$$ orbital is more attracted towards the nucleus. Hence, greater amount of energy is required for the removal of this valence electron from $$X$$ as compared to $$Y.$$
23.
To which group, an element with atomic number 88 will belong?
A
Group 12
B
Group 17
C
Group 10
D
Group 2
Answer :
Group 2
$$Z = 88,\left[ {Rn} \right]7{s^2},$$ hence belongs to group 2.
24.
The electronegativity of the following elements increases in the order
A
$$C,N,Si,P$$
B
$$N,Si,C,P$$
C
$$Si,P,C,N$$
D
$$P,Si,N,C$$
Answer :
$$Si,P,C,N$$
NOTE: Electronegativity increases on moving from left to right in a period and decreases on moving from top to bottom in a group.
$$Si$$ and $$P$$ are placed in the $${3^{{\text{rd}}}}$$ period while $$C$$ and $$N$$ are placed in the $${2^{{\text{nd}}}}$$ period. Elements in $${2^{{\text{nd}}}}$$ period have higher electronegativities than those in the $${3^{{\text{rd}}}}$$ period. Since $$N$$ has smaller size and higher nuclear charge than $$C,$$ its electronegativity is higher than that of $$C.$$ Similarly, the electronegativity of $$P$$ is higher than that of $$Si$$ . Thus, the overall order is : $$Si,P,C,N.$$
25.
Fill in the blanks with appropriate option.
The ability of an atom to attract shared electrons to itself is called $$\underline {\left( {\text{i}} \right)} .$$ It is generally measured on the $$\underline {\left( {{\text{ii}}} \right)} $$ scale. An arbitrary value of $$\underline {\left( {{\text{iii}}} \right)} $$ is assigned to fluorine ( have greatest ability to attract electrons ). It generally $$\underline {\left( {{\text{iv}}} \right)} $$ across a period and $$\underline {\left( {\text{v}} \right)} $$ down a group.
(i)
(ii)
(iii)
(iv)
(v)
(a)
polarity
Pauling
2.0
decreases
increases
(b)
electro-negativity
Pauling
4.0
increases
decreases
(c)
valency
Mulliken
1.0
decreases
increases
(d)
electron affinity
Mulliken
2.0
increases
increases
A
(a)
B
(b)
C
(c)
D
(d)
Answer :
(b)
No explanation is given for this question. Let's discuss the answer together.
26.
The oxidation state of an element in a particular compound can be defined as
A
the charge acquired by its atom on the basis of electronegative consideration from other atoms in the molecule
B
the residual charge acquired by its atom after removing all electronegative atoms from the molecule
C
the valency of the most electronegative atom present in the molecule
D
total number of electrons accepted by an atom to form a molecule
Answer :
the charge acquired by its atom on the basis of electronegative consideration from other atoms in the molecule
No explanation is given for this question. Let's discuss the answer together.
27.
Elements $$X, Y$$ and $$Z$$ have atomic numbers $$19, 37$$ and $$55$$ respectively. Which of the following statements is true about them ?
A
Their ionization potential would increase with increasing atomic number
B
$$'Y'$$ would have an ionisation potential between those of $$'X'$$ and $$'Z'$$
C
$$'Z'$$ would have the highest ionization potential
D
$$'Y'$$ would have the highest ionization potential.
Answer :
$$'Y'$$ would have an ionisation potential between those of $$'X'$$ and $$'Z'$$
Elements $$X, Y, Z$$ with atomic numbers $$19, 37, 55$$ lie in group 1 (alkali metals). On moving down a group from the size of atoms increases, the outermost electrons become less strongly held. So the ionization energy decreases. Therefore, $$IE$$ of $$Y$$ could be between those of $$X$$ and $$Z.$$
\[\begin{matrix}
{} \\
{} \\
I.E. \\
\end{matrix}\,\,\,\begin{matrix}
X \\
K\left( 19 \right) \\
4.3 \\
\end{matrix}\,\,\,\begin{matrix}
Y \\
Rb\left( 37 \right) \\
4.2 \\
\end{matrix}\,\,\,\begin{matrix}
Z \\
Cs\left( 55 \right) \\
3.9 \\
\end{matrix}\]
28.
In which of the following, the order is not in accordance with the property mentioned.
29.
The formation of the oxide ion $$O_{\left( g \right)}^{2 - }$$ requires first an exothermic and then an endothermic step as shown below
$$\eqalign{
& {O_{\left( g \right)}} + {e^ - } = O_{\left( g \right)}^ - \,\,\Delta {H^ \circ } = - 142\,kJmo{l^{ - 1}} \cr
& {O^ - }\left( g \right) + {e^ - } = O_{\left( g \right)}^{2 - }\,\,\Delta {H^ \circ } = 844\,kJmo{l^{ - 1}} \cr} $$
This is because
A
$${O^ - }$$ on will tend to resist the addition of another
electron
B
Oxygen has high electron affinity
C
Oxygen is more elecronegative
D
$${O^ - }$$ ion has comparatively larger size than oxygen atom
Answer :
$${O^ - }$$ on will tend to resist the addition of another
electron
$${O^ - }$$ ion exerts a force of repulsion on the incoming electron. The energy is required to overcome it.
30.
Why is the electron gain enthalpy of $$O$$ or $$F$$ less than that of $$S$$ or $$Cl?$$
A
$$O$$ and $$F$$ are more electronegative than $$S$$ and $$Cl.$$
B
When an electron is added to $$O$$ or $$F,$$ it goes to a smaller $$\left( {n = 2} \right)$$ level and suffers more repulsion than the electron in $$S$$ or $$Cl$$ in larger level $$\left( {n = 3} \right).$$
C
Adding an electron to $$3p$$ -orbital leads to more repulsion than $$2p$$ -orbital.
D
Electron gain enthalpy depends upon the electron affinity of the atom.
Answer :
When an electron is added to $$O$$ or $$F,$$ it goes to a smaller $$\left( {n = 2} \right)$$ level and suffers more repulsion than the electron in $$S$$ or $$Cl$$ in larger level $$\left( {n = 3} \right).$$
There is more repulsion for the incoming electron when the size of atom is smaller.