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.
51.
Which group of elements shows lowest ionisation enthalpy?
A
Alkali metals
B
Alkaline earth metals
C
Halogens
D
Noble gases
Answer :
Alkali metals
Alkali metals shows lowest ionization energy because of higher atomic radii due to which outermost electron is far from the nucleus and can easily be removed.
52.
An element $$X$$ occurs in short period having configuration $$n{s^2}n{p^1}.$$ The formula and nature of its oxide is
A
$$X{O_3},{\text{basic}}$$
B
$$X{O_3}\,{\text{acidic}}$$
C
$${X_2}{O_3},\,{\text{amphoteric}}$$
D
$${X_2}{O_3}\,{\text{basic}}$$
Answer :
$${X_2}{O_3},\,{\text{amphoteric}}$$
$$n{s^2}n{p^1}$$ is the electronic configuration of $${\text{III}}\,A$$ period. $$A{l_2}{O_3}$$ is amphoteric oxide
53.
Elements belonging to the same group of periodic table have
A
same number of energy levels
B
same number of valence electrons
C
same number of electrons
D
same ionisation enthalpy
Answer :
same number of valence electrons
No explanation is given for this question. Let's discuss the answer together.
54.
Which of the following oxides is not expected to react with sodium hydroxide?
A
$${B_2}{O_3}$$
B
$$CaO$$
C
$$Si{O_2}$$
D
$$BaO$$
Answer :
$$CaO$$
Sodium hydroxide, $$NaOH,$$ being a strong alkali
never react with a basic oxide (compound). Among
the given options, $${B_2}{O_3}$$ and $$BeO$$ are amphoteric oxides, $$Si{O_2}$$ is an acidic oxide and $$CaO$$ is a basic oxide. Therefore, $$NaOH$$ does not react with $$CaO.$$
55.
The incorrect statement among the following is
A
the first ionization potential of $$Al$$ is less than the first ionization potential of $$Mg$$
B
the second ionization potential of $$Mg$$ is greater than the second ionization potential of $$Na$$
C
the first ionization potential of $$Na$$ is less than the first ionization potential of $$Mg$$
D
the third ionization potential of $$Mg$$ is greater than the third ionization potential of $$Al.$$
Answer :
the second ionization potential of $$Mg$$ is greater than the second ionization potential of $$Na$$
$$I{E_2}$$ of $$Mg$$ is lower than that of $$Na$$ because in case of $$M{g^ + },3s$$ - electron has to be removed where as in case of $$N{a^ + },$$ an electron is removed from the stable inert gas configuration which is difficult.
56.
Examples of elements belonging to $$s,p,d$$ or $$f$$ - block are given below. Identify the wrong example.
A
$$s$$ - block element - Caesium
B
$$p$$ - block element - Barium
C
$$d$$ - block element - Chromium
D
$$f$$ - block element - Thorium
Answer :
$$p$$ - block element - Barium
Barium belongs to $$s$$ - block with an outer configuration $$6{s^2}.$$
57.
Similarity in chemical properties of the atoms of elements in a group of the Periodic table is most closely related to :
A
atomic numbers
B
atomic masses
C
number of principal energy levels
D
number of valence electrons
Answer :
atomic numbers
If elements are arranged in order of their increasing atomic numbers, element coming at intervals of $$2, 8, 8, 18, 18, 32$$ and $$32$$ will have similar physical and chemical properties and thus grouped in one particular group.
58.
The first ionisation potential of $$Na$$ is $$5.1\,eV.$$ The value of
electron gain enthalpy of $$N{a^ + }$$ will be :
59.
The first ionization enthalpies of $$Na,Mg,Al$$ and $$Si$$ are in the order
A
$$Na < Mg > Al < Si$$
B
$$Na > Mg > Al > Si$$
C
$$Na < Mg < Al < Si$$
D
$$Na > Mg > Al < Si$$
Answer :
$$Na < Mg > Al < Si$$
As we move across the period, atomic size decreases hence, ionisation enthalpy increases. But for $$Al\left( {3{s^2}3{p^1}} \right),$$ electron has to be removed from outer $$3p$$ orbital whereas in $$Mg\left( {3{s^2}} \right),$$ electron has to be removed from stable fully filled $$3s$$ orbital. Thus, $$I.E.$$ for $$Mg > Al.$$ So, the correct order of first ionisation enthalpies is : $$Na < Mg > Al < Si$$
60.
Which one of the following has largest ionic radius?
A
$$L{i^ + }$$
B
$$O_2^{2 - }$$
C
$${B^{3 + }}$$
D
$${F^ - }$$
Answer :
$$L{i^ + }$$
On moving along a period ionic radii decreases due to increase in effective nuclear charge.