# MCQ Questions for Class 11 Chemistry Chapter 3 Classification of Elements and Periodicity in Properties with Answers

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## Classification of Elements and Periodicity in Properties Class 11 MCQs Questions with Answers

Multiple Choice Type Questions

Question 1.
The set representing the correct order of first ionization potential is
(a) K > Na > Li
(b) Be > Mg > Ca
(c) B > C > N
(d) Ge > Si > C.

Answer: (b) Be > Mg > Ca

Question 2.
The increasing order of the a tomifc radius for the elements Na, Rb, K and Mg is
(a) Na < K < Mg < Rb
(b) K < Na < Mg < Rb
(c) Na < Mg < K < Rb
(d) Mg < Na < K < Rb

Answer: (d) Mg < Na < K < Rb

Question 3.
The correct’ order of the first ionization potentials among the following elements: Be, B, C, N Q is
(a) B < Be < C < O < N
(b) B < Be < C < N < O
(c) Be < B < C < N < O
(d) Be < B < C < O < N

Answer: (a) B < Be < C < O < N

Question 4.
Correct order of ionization enthalpies is
(a) Zn < Cd < Hg
(b) Cd < Hg < Zn
(c) Na > Cs > Rb
(d) Cs < Rb < Na

Answer: (d) Cs < Rb < Na

Question 5.
(a) N < Be < B
(b) F < O2- < N3-
(c) Na < Li < K
(d) Fe3+ < Fe2+ < Fe4+

Answer: (b) F < O2- < N3-

Question 6.
Set containing isoelectronic species is
(a) C$$_{2}^{2-}$$, NO+, CN, O$$_{2}^{2+}$$
(b) CO, NO, O2 CN
(c) CO2, NO2, O2, N2O
(d) CO, CO2, NO, NO2

Answer: (a) C$$_{2}^{2-}$$, NO+, CN, O$$_{2}^{2+}$$

Question 7.
Which of the following is most electronegative?
(a) Carbon
(b) Silicon
(d) Tin

Question 8.
The values of electronegativity of atoms A and B are 1.20 and 4.0 respectively. The percentage of ionic character of A-B bond is
(a) 50%
(b) 72.24%
(c) 55.3%
(d) 43%

Question 9.
Tick the correct order of second ionisation energy in the following
(a) F > O > N > C
(b) O > F > N > C
(c) O > N > F > C
(d) C > N > O > F

Answer: (b) O > F > N > C

Question 10.
Consider the isoelectronic series : K+, S2-, Cl1- and Ca2+, the radii of the ions decrease as
(a) Ca2+ < K+ > Cl, S2-
(b) Cl > S2- > K+ > Ca2+
(c) S2- > Cl > K+ > Ca2+
(d) K+ > Ca2+ > S2- > Cl.

Answer: (c) S2- > Cl > K+ > Ca2+

Question 11.
The radii of F, F, O, D2- are the order of
(a) O2- > F > F > O
(b) F > O2- > F > O
(c) O2- > O > F > F
(d) O2- > F > O > F

Answer: (d) O2- > F > O > F

Question 12.
Among the following groupings which represents the collection of isoelectronic species.
(a) NO+, C$$_{2}^{2-}$$, CO$$_{2}^{-}$$, CO
(b) N2, C$$_{2}^{2-}$$, CO, NO
(c) CO, NO+, CN, C$$_{2}^{2-}$$
(d) NO, CN, N2, O$$_{2}^{-}$$

Answer: (c) CO, NO+, CN, C$$_{2}^{2-}$$

Question 13.
According to the periodic law of elements the variation in properties of elements is related to their
(a) nuclear neutron-proton number ratio
(b) atomic masses
(c) nuclear masses
(d) atomic numbers.

Question 14.
The ions O2+, F, Na+, Mg2+ and Al3+ are isoelectronic, their ionic radii show.
(a) a significant increase from O2- to Al3+
(b) an increase from O2- to F and then decrease from Na+ to Al3+
(c) a significant decrease from O2- to Al3+
(d) a decrease from O2- to F and then increase from Na+ to Al3+.

Answer: (c) a significant decrease from O2- to Al3+

Question 15.
The ionic radii of isoelectronic species N3-, O2- and F in Å are in the order.
(a) 1.36, 1.40, 1.71
(b) 1.36, 1.71, 1.40
(c) 1.71, 1.40, 1.36
(d) 1.71, 1.36, 1.40

Question 16.
Which of the following groupings represents a collection of isoelectronic species? [At. Nos. Cs = 55, Br = 35]
(a) Ca2+, Cs, Br
(b) Na+, Ca2+, Mg2+
(c) N3-, F, Na+
(d) Be, Al3+, Cl

Question 17.
Identify the least stable ion amongst the following.
(a) Li
(b) Be
(c) B
(d) Cr

Question 18.
The group of elements in which the differentiating electron enters the antepenultimate shell of the atoms are called
(a) f-block
(b) p-block
(c) s-block
(d) d-block

Question 19.
Pick out the isoelectronic structures from the following
(I) CH$$_{3}^{+}$$
(II) H3O+
(III) NH3
(IV) CH$$_{3}^{-}$$
(a) I and II
(b) III and IV
(c) I and III
(d) II, III and IV

Answer: (d) II, III and IV

Question 20.
Eka-alurninium and Eka-silicon are known as
(a) GalliAn and germanium
(b) Aluminium and silicon
(c) Iron and sulphur
(d) Neutron and magnesium

Question 21.
Element with atomic number 56 belongs to which block?
(a) s
(b) p
(c) d
(d) f

Question 22.
Which of the following is the smallest cation?
(a) Na+
(b) Mg2+
(c) Ca2+
(d) Al3+

Question 23.
The first ionisation energy for Li is 5.4 eV and electron affinity of Cl is 3.61 eV. The ∆H (in k] mol-1) for the reaction.
Li (g) + Cl (g) → Li+ (g) + Cl (g) if the resultant ions do not combine with each other is [1eV = 1.6 × 10-19 J]
(a) 70
(b) 100
(c) 170
(d) 270

Question 24.
Which of the following processes involves absorption of energy?
(a) Cl + e → Cl
(b) O + e → O2-
(c) O + e → O
(d) s + e → s

Answer: (b) O + e → O2-

Question 25.
In which of the following compounds does che ratio of the anion si/e to cation size has the lowest value?
(a) CsI
(b) Li I
(c) LiF
(d) CsF

Question 26.
Which of the following represents most electropositive element?
(a) [He]2s1
(b) [He]2s²
(c) [Xe]6s1
(d) [Xe]6s²

Question 27.
An element with atomic number 106 has been discovereq recently. Which of the following electronic configuration will it have
(a) [Rn]5f146d47s²
(b) [Rn]5f146d57s1
(c) [Rn]5f14 6d67s0
(d) 5f146d7s²7p³

Question 28.
If the ionic radii of K+ and F are about 1.34 Å each, then the expected values of atomic radii of K and F should be respectively
(a) 2.31 and.0.64 Å
(b) 2.31 and 1.34 Å
(c) 0.64 and 2.31 Å
(d) 1.34 and 1,34 Å

Question 29.
Total number of elements present in the 3rd period is
(a) 6
(b) 32
(c) 18
(d) 8

Question 30.
The number of periods in the periodic table is
(a) 6
(b) 7
(c) 8
(d) 10

Question 31.
Total number of vertical columns (groups) in the long form of the periodic table is
(a) 8
(b) 18
(c) 17
(d) 16

Question 32.
The general outer electronic configuration of transition elements is
(a) ns²nd1-10
(b) ns²np1(n – 1)d1-10
(c) ns²np6(n – 1)d1-10
(d) ns0-2 (n – 1)d1-10

Answer: (d) ns0-2 (n – 1)d1-10

Question 33.
The correct order of electron affinities is
(a) 0 > S > Se
(b) 0 < S < Se
(c) 0 < Se < S
(d) S < Se < 0

Answer: (c) 0 < Se < S

Question 34.
The first ionisation energy will be maximum for
(a) Uranium
(b) Hydrogen
(c) Lithium
(d) Iron

Question 35.
Which of the following has least electron affinity?
(a) Oxygen
(b) Argon
(c) Nitrogen
(d) Boron

Question 36.
The elements in which 4f orbitals are progressively filled are called
(a) Actinides
(b) Transitibn elements
(c) Lanthanides
(d) Halogens

Question 37.
The band length in LiF will be
(a) Less than that of NaF
(b) Equal to that of KF
(c) More than that of KF
(d) Equal to that of NaF

Answer: (a) Less than that of NaF

Question 38.
The ionic radius of Cr is minimum in which of the following compounds?
(a) K2CrO4
(b) CrF3
(c) CrO2
(d) CrCl3

Question 39.
Which of the following atoms would be paramagnetic?
(a) Ca
(b) Be
(c) Zn
(d) N

Question 40.
Which one of the following is the Correct order of size?
(d) I > I > I+
(b) I > I+ > I
(c) I+ > I > 1
(d) I > I > I+

Answer: (d) I > I > I+

Fill in the Blanks

Question 1.
According to modern-periodic law, the properties of the elements are a periodic function of their ………………….

Question 2.
The cause of periodicity in properties of the elements is …………………. electronic configuration in the valence shells of their atoms.

Question 3.
The elements of group 16 are called as ………………….

Question 4.
Size of the atoms …………………. from left to right across a period and …………………. and descending a group.

Question 5.
The vertical columns in periodic table are called …………………. These are …………………. in all.

Question 6.
Electronegativity generally …………………. in going from left to right across a period and …………………. in going from top to bottom in a group.

Question 7.
In the long form of the periodic table each period starts with an …………………. metal and ends with a ………………….

Question 8.
Metallic character …………………. as we move down a group and …………………. as we go from left to right across a period.

Question 9.
The atomic radius of potassium is …………………. than that of lithium.

Question 10.
Lithium …………………. with magnesium in its properties because it has …………………. relationship with it.

True or False Statements

Question 1.
The size of Cl ion Is smaller than that of S2- ion.

Question 2.
The decreasing order of electron affinity of F, Cl, Br is F > Cl > Br.

Question 3.
The first ionisation enthalpy of N is lower than that of O.

Question 4.
The size decreases as Cu > Cu+ > Cu2+.

Question 5.
An element with atomic number 46 is a transition element.

Question 6.
The element Hafnium (Hf) with atomic number 72 belongs to f-block.

Question 7.
The second electron gain enthalpy of oxygen is negative.

Question 8.
There are 7 periods and 18 groups in the long form of Periodic Table.

Question 9.
Fe3+ has more unpaired electrons than Fe2+.

Question 10.
The radii of Fe, Fe3+, Fe2+ decrease in the order Fe > Fe2+ > Fe3+.

Match Type Questions

 Column I Column II 1. 21Sc to 30Zn (a) 4d series 2. 39Y to 48Cd (b) 3d series 3. 57La, 72Hf to 80Hg (c) 6d series 4. 89AC, 104Ku, 105Ha, 112Eka (d) Actinide series 5. 90Th to 103Lr (e) 5d series