Classification of Elements and Periodicity in Properties MCQs – 1

1) The number of electrons in the nucleus of Cl is:
a) 6
b) 12
c) 17
d) Zero

2) The radioactive decay of 35X88 by a -particle emission produces an unstable nucleus which spontaneously emits a neutron. The final product is

3) In the nuclear reaction 92 U238 82Pb206, the number of alpha particles and beta particles emitted are:

4) 92U235 + n 92 U236Fission product + neutron + 19.293 x 109 J. The energy released when 1 g of 92U235 undergoes fission is

5) A positron is
a) An electron with a positive charge
b) A helium atom
c) A nucleus with two protons
d) A nucleus with one neutron and one proton

6) The half-life of a radioactive substance is 100days. After 400 days, one gm of element will be reduced to
a) 0.5 g.
b) 0.25 g.
c) 0.0625 g.
d) 0.125g.

7) In the reaction 7N14 + 2He4aXb + 1H1, the nucleus X is?
a) N-16
b) N-17
c) O-18
d) O-17

8) The half-life of a radioactive substance is 60 min. During 3 hours, the fraction of total number of atoms that have decayed would be
a) 12.5%
b) 87.5%
c) 8.5%
d) 25%

9) In radioactive transformation 92U238 82Pb206, the number of – and -particles emitted are
c) 4 Protons, 8 neutrons
d) 6 electrons, 8 protons

10) Radioactivity is due to a
a) Stable electronic configuration
b) Stable nucleus
c) Unstable nucleus
d) Unstable electronic configuration

11) Which of the following nuclei is unstable?

12) Which is the missing particle in the reaction, 3Li7+ 21H 83Li + x
a) Proton
b) Deutron
c) Positron

13) If 92U235 is assumed to decay only by emitting and one -particle, the possible product of decay is:

14) The isotopic mass of 92U238 is 238.125 amu. Its packing fraction is
a) 5.25
b) 0.125
c) 12.5
d) 1.25

15) A radioactive sample has a half-life of 1500 years. A sealed tube containing 1 g of a sample will contain Â… g of the sample after 3000 years .The missing figure is
a) 1g.
b) 0.5 g.
c) 0.25 g.
d) 0.0 g.

16) In a nuclear explosion, the energy is released in the form of
a) Electrical energy
b) Potential energy
c) Thermal energy
d) Kinetic energy

17) Gamma rays are
a) High energy electrons
b) Low energy electrons
c) High energy electromagnetic waves
d) High energy positron

18) The radiation with high penetrating power and not affected by an electric or magnetic field is
b) Neutrons

19) 84Po210 82Pb206 + 2He4. In this reaction predict the position of the group of Po when lead is in IV B group
a) II A
b) IV B
c) VI B
d) VI A

20) Which nuclide is radioactive?
a) C-12
b) H-2
c) O-16
d) both C-14 and H-3

21) The carbon dating method is based on the fact that
a) C-14 fraction is same in all the objects
b) C-14 is highly insoluble
c) The ratio of C-14 and C-12 is constant in living species
d) All

22) The nucleus of an atom is made up of X protons and Y neutrons. For the most abundant and stable nuclei,
a) X and Y are both even
b) X and Y are both odd
c) X is even, Y is odd
d) X is odd, Y is even

23) The number of emitted by 84Ra21882Pb206 is
a) 3
b) 4
c) 6
d) 2

24) – particles emitted from a radioactive element are identified with electrons. Each electron emitted by – rays emission comes from
a) The orbital electron of the atom
b) The nucleus of the atom
c) A proton in the nucleus
d) A neutron in the nucleus

25) The nuclear reaction is called the
a) Fission reaction
b) Fusion reaction
c) Chain reaction
d) Thermal reaction

26) Which of the following ages cannot be determined by radioactive carbon dating?
a) Remains of animals
b) Samples of rock from an old mountain
c) A thousand year old tree
d) An old piece of wood

27) From the reaction given below deduce the group of polonium in the periodic table. (Pb belongs to the 14th group)
a) 2
b) 14
c) 6
d) 16

28) The radioactivity due to the C-14 isotope (half life = 6000 years) of a sample of wood from an ancient tomb was found to be nearly half that of fresh wood. The tomb is therefore about
a) 3000 yr old
b) 6000 yr old
c) 9000 yr old
d) 12000 yr old

29) An element is isobaric with the inert gas atom . The electronic arrangement of the element is 1s2 2s2 2p6 3s2 3p6 4s2. How many neutrons does each atom of the element carry in its nucleus ?
a) 22
b) 20
c) 18
d) 16

30) A sample of radioactive element with a half-life period of one year weighs 100 mg. After two years, the weight of the remaining element in mg is
a) 50
b) 25
c) 12.5
d) 6.25

31) The energy released in an atom bomb explosion is mainly due to?
a) Release of electrons
b) Release of neutrons
c) reduction in the mass of products from the initial material
d) Greater mass of products than initial material

32) When U- 238 is bombarded it is converted into fissionable
a) Th
b) U- 235
c) Pu- 239
d) Pb

33) The energy released during the fission of 1 kg of uranium is

34) Tritium undergoes radioactive decay giving
c) Neutrons
d) None

35) When beryllium is bombarded with -particles (the Chadwick experiment), extremely penetrating radiations which cannot be deflected by electrical or magnetic fields are given out. These are
a) Protons
b) A beam of electrons
c) A beam of neutrons
d) A beam of neutrons and protons

36) A radioactive isotope has a half-life of 10 days. If today there are 125 gms of it left, what was its original weight 40 days earlier?
a) 600 g
b) 1000 g
c) 1250 g
d) 2000 g

37) The rays whose range in air is very small are
d) X-rays

38) Many elements have non-integral masses because
a) They have isotopes
b) Their isotopes have non-integral masses
c) Their isotopes have different masses
d) The constituent neutrons, protons and electrons, combine to give fractional masses

39) A radioactive element has a half-life of 20 minutes. How much time should elapse before the element is reduced to 1/8 of its original value?
a) 40 min
b) 60 min
c) 80 min
d) 160 min

40) Atoms of different elements having identical masses are known as
a) Isotopes
b) Isobars
c) Isotones
d) Isomers

41) Which of the following has the highest mass?
a) a neutron
b) Tritium
c) Deuterium

42) Living things contain C12 and C13. C12 is stable and C13 decays and declines in proportional quantity. The technique that uses this principle for determining the age of fossils, skeletons, old trees and dinosaurs is called
a) C-12 dating
b) Radiocarbon dating
c) Carbon age
d) Fossil carbon

43) 0ne mole of electrons is the same as a
a) Ampere
b) Unit charge
c) Faraday
d) Coulombs

44) In a chain reaction the uranium atom gets fissioned forming two different materials. The total weight of these put together is
a) More than the weight of the parent uranium atom
b) Less than the weight of the parent uranium atom
c) More or less depending upon the experimental conditions
d) Neither more nor less

45) One micro Curie is equal to …… disintegrations per second.

46) Nuclear energy is the result of conversion of
a) Neutrons to protons
b) Protons to neutrons
c) Mass into energy
d) None

47) Which of the following is a major hurdle in finding ways to properly harness nuclear fusion energy on a commercial scale in an effort to solve the energy crisis?
a) Purification of raw materials
b) Finding safe ways to dispose of the waste products
c) To maintain high temperatures for the reaction
d) Non-availability of skilled scientists

48) The most significant contribution towards the development of periodic table was made by
a) Mendeleev
b) Avogadro
c) Dalton
d) Cavendish

49) Mendeleevs periodic law is based on the
a) Atomic number
b) Atomic weight
c) Equivalent weight
d) Valency

50) Which is the incorrect statement in respect of Mendeleevs periodic table?
a) It has made the study of elements easier and systematic
b) It has helped in correcting doubtful atomic weights
c) It has paved the way for the discovery of new elements
d) None of the above

51) The two places left empty by Mendeleev in the periodic table were for
a) Aluminum and silicon
b) Gallium and germanium
c) Arsenic and antimony
d) Antimony and bismuth

52) Gallium was named by Mendeleev as
a) Eka-aluminium
b) Eka-silicon
c) Eka-germanium
d) Eka-zinc

53) Which element was named eka-silicon in Mendeleevs classification of elements?
a) Germanium
b) Gallium
c) Indium
d) Thallium

54) Which of the following statements is not correct about the modified Mendeleevs periodic table?
a) It consists of nine groups and seven periods
b) Group VIII like groups I-VII has been divided into two sub-groups A and B
c) The group of an element in the periodic table represents its valency
d) The elements of group IB are called coinage metals.

55) The scientist responsible for the addition of the zero group to Mendeleev’s original periodic table was
a) Ramsay
b) Rutherford
c) Bohr
d) Planck

56) The modern periodic law states that the physical and chemical properties of elements are a periodic function of their
a) Ionisation energies
b) Atomic masses
c) Atomic numbers
d) Atomic volumes

57) The modern periodic table is based on the atomic numbers of elements. The experiment which proved the significance of the atomic number was
c) the discovery of X-rays by Roentgen

58) The cause of the periodicity of properties is the
a) Increasing number of atomic radius
b) Increasing atomic weights
c) Number of electrons in the valency orbit
d) recurrence of similar outer electronic configurations.

59) The phrase “periodicity in the properties of elements” means that when elements are arranged in the increasing order of their atomic weights or atomic numbers, similar elements
a) Recur after a fixed interval
b) Recur after certain regular intervals
c) Form vertical groups
d) Form horizontal groups

60) Certain regular intervals after which the outer electronic configurations of the elements recur are called
a) Magic numbers
b) Atomic numbers
c) Gold number
d) Avogadro number

61) As applied to the periodic table, which of the following sets include only magic numbers?
a) 2,8,20,28,50,82,126
b) 2,8,8,18,18,32
c) 2,2,8,8,18,32
d) 2,8,18,18,32,32

62) On the basis of electronic configuration, all the elements in the long form of the periodic table have been grouped in
a) 3 blocks
b) 4 blocks
c) 4 blocks + lanthanides
d) 3 blocks + lanthanides + actinides

63) Alkali and alkaline earth metals belong to the
a) s-Block of elements
b) p-Block of elements
c) d-Block of elements
d) f-Block of elements

64) Elements whose outer electronic configuration vary from ns2np1 to ns2np6 constitute the
a) s-block of elements
b) p-block of elements
c) d-block of elements
d) f-block of elements

65) The elements of groups 1,2,13,14,15,16 and 17 are collectively called
a) Noble gases
b) Representative or normal elements
c) Transition elements
d) Inner transition elements

66) Group 18 (or zero group) elements are best termed
a) Inert gases
b) Rare gases
c) Noble gases
d) Inactive gases

67) Incompletely filled orbitals in the representative elements are the
a) s- and p-orbitals.
b) d- orbitals only
c) f- orbitals only
d) Both d- and f- orbitals

68) Representative elements belong to the
a) s- and p-blocks
b) p- and d-blocks
c) f- block only
d) d- and f-blocks

69) Elements whose atoms have two incomplete outermost shells are called
a) s-block elements
b) p-block elements
c) d-block elements
d) f-block elements

70) Which of the following are shown separately at the bottom of the periodic table?
a) 3d-block elements
b) 4d-block elements
c) 5d-block elements
d) Inner transition elements

71) The fourteen elements collectively placed in group3 (or IIIB) and the 7th period are called
a) d-block of elements
b) p-block of elements
c) s-block of elements
d) Actinides

72) The name rare earths is used for
a) Lanthanides only
b) Actinides only
c) Both lanthanides and actinides
d) Alkaline earth metals

73) The elements which are characterised by the outer shell electronic configuration from ns1 to ns2 np5 are collectively called
a) Transition elements
b) Inner transition elements
c) Representative elements
d) Actinides

74) In the modern periodic table VI period contains
a) 32 elements
b) 18 elements
c) 30 elements
d) 8 elements

75) Which one of the following is not a characteristic of p- block elements?
a) The last electron in them enters into a p-orbital
b) They mostly form covalent compounds
c) In any row, the metallic character decreases from left to right
d) The oxidizing power decreases from left to right

76) f-block elements are called inner transition elements because
a) They have properties similar to those of transition elements
b) They have taken out of the transition elements
c) The last electron enters into the f-orbital of the penultimate shell
d) The last electron enters into the f-orbital of the ante-penultimate shell

77) The 3rd period of the periodic table contains
a) 8 elements
b) 32 elements
c) 18 elements
d) 19 elements

78) Which of the following about the 6th period of the periodic table is incorrect?
a) Two s-block and six p-block elements
b) Fourteen f-block elements
c) Ten d-block elements
d) None of the above

79) The 3d-transition series contains elements having atomic numbers ranging from
a) 22 to 30
b) 21 to 30
c) 21 to 31
d) 21 to 29

80) Elements with atomic number 93 onwards are called
a) Actinides
b) Lanthanides
c) Transuranics
d) Rare earths

81) An element has three electrons in the 4th shell. The atomic number of the element is
a) 13
b) 21
c) 27
d) 31

82) The quantum numbers of the last electron which enters an element are:

I=3, m=-2 and s=+1/2.

In which block of the periodic table is this element present?
a) s-Block
b) p-Block
c) d-Block
d) f-Block

83) In general, the outer electronic configuration of the elements of group 6 is

84) The element with the electronic configuration [Xe] 4f 7 5d 1 6s 2 lies in the
a) s-Block
b) d-Block
c) f-Block
d) Actinide series

85) The atom having the valence shell electronic configuration 4s2 4p2 would be in
a) Group 2 or IIA and period 3
b) Group 12 or IIB and period 4
c) Group 14 or IVA and period 4
d) Group 14 or IVA and period 3

86) The element with atomic number 57 belongs to the
a) Lanthanides
b) Actinides
c) Transition elements
d) s-Block

87) Which one of the following is an alkaline earth metal?

88) An element, which lies in the same group of the periodic table as mercury, is
a) Cadmium
b) Gold
c) Tin
d) Thallium

89) Which pair of elements is from the same group of the periodic table?
a) Cl, Br
b) Na, Ca
c) K, Br
d) Cl, Li

90) Choose the set of atomic numbers of four elements, which lie in the same group of the periodic table:
a) 2,18,30,36
b) 8,18,36,84
c) 18,32,54,86
d) 2,18,36,54

91) Select from the following sets the elements belonging to the same group of the periodic table.
a) Z=11,3,20,37
b) Z=12,38,4,88
c) Z=31,13,81,50
d) Z=21,39,90,57

92) Which of the following sets includes only transition elements?
a) Z=11,14,22,42
b) Z=13,33,54,83
c) Z=24,39,74,80
d) Z=19,32,51,101

93) One would expect the atomic structure of silicon to be similar to that of
a) Zinc
b) Diamond
c) Sulphur
d) Magnesium

94) Which pair of the elements whose atomic numbers are given will have the same chemical properties?
a) 13,22
b) 3,11
c) 4,24
d) 2,1

95) The physical properties of vanadium are more closely related to
a) Titanium
b) Tungsten
c) Niobium
d) Nobelium

96) Which of the following sets is a pair of elements that do not belong to the same group but show chemical resemblance?
a) B, Al
b) Be, Al
c) Zr, Hf
d) K, Rb

97) Diagonal relationship is shown by certain elements of the —- periods
a) 2nd and 3rd
b) 3rd and 4th
c) 4th and 5th
d) 1st and 2nd

98) The cause of the diagonal relationship between elements is
a) Similar electronegativities
b) Similar ionic or atomic radii
c) Similar polarising power of ions
d) All are correct

99) Aluminium is diagonally related to
a) Li
b) Be
c) Na
d) B

100) A diagonal relationship exists between
a) Li and Mg
b) Na and Mg
c) K and Mg
d) Al and Mg


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