MCQ questions and answers for Isotopes, Isobars and Isotones
1. The atoms of an element which have
the same number of protons and different number of neutrons are called_______
(a) isotopes
(b) isobars
(c) isotones
(d) isomers
Answer. (a)
2. Isotopes of an element have _______
atomic number but _______ mass numbers.
(a) same, same
(b) different, same
(c) same, different
(d) different, different
Answer. (c)
3. _____occupy the same place in the
periodic table.
(a) isobars
(b) isotopes
(c) isotones
(d) none of these
Answer. (b)
4. Isotopes have _______ chemical
properties.
(a) same
(b) similar
(c) different
(d) none of these
Answer. (b)
5. The electronic configuration of
isotopes of an element is _______.
(a) same
(b) similar
(c) different
(d) none of these
Answer. (a)
6. The physical properties of the
isotopes which depend on the _______ of the atoms are used to separate them.
(a) electronic configuration
(b) mass
(c) velocity
(d) valence electrons
Answer. (b)
7. The mass number A is given by
_______ (Z is atomic number and N is number of neutrons)
(a) A = Z – N
(b) A = Z + N
(c) A = N – Z
(d) A = 2 (Z + N)
Answer. (b)
8. An atom of _______ contains no
neutrons.
(a) hydrogen
(b) deuterium
(c) tritium
(d) none of these
Answer. (a)
9. The difference between the number of
neutrons and the protons is positive for _______
(a) hydrogen atom
(b) deuterium atom
(c) tritium atom
(d) none of these
Answer. (c)
10. An element with atomic number equal
to one, exists in three isotopes namely 1H1 , 2H1 and 3H1.
Which out of these has only one electron in its outermost shell?
(a) 1H1
(b) 2H1
(c) 3H1
(d) all the three
Answer. (d)
11. In which isotope of oxygen out of O16,
O17 and O18 there are equal number of protons,
electrons and neutrons?
(a) O16
(b) O17
(c) O18
(d) none of these
Answer. (a)
12. Which isotope of chlorine out
of 35Cl17 and 37Cl17 has
greater number of neutrons than the protons?
(a) 17Cl35
(b) 17Cl37
(c) neither of the two
(d) both
Answer. (d)
13. The reaction rates of the individual
isotopes are_______
(a) the same
(b) different
(c) sometimes the same, sometimes different
(d) none of these
Answer. (b)
14. The atoms which have the same mass
number but different atomic numbers are called_______
(a) isobars
(b) isotopes
(c) isotones
(d) isomers
Answer. (a)
15. Which is true about the isobars?
(a) they have same mass number and same atomic number
(b) they have same mass number and different atomic number
(c) they have different mass number and same atomic number
(d) they have different mass number and different atomic
number
Answer. (b)
16. Which of the following statements
holds good for 40Ar18 , 40K19 and 40Ca20 ?
(a) they have equal number of protons and electrons
(b) they have equal number of protons and neutrons taken
together
(c) they have equal number of neutrons in their respective
nuclei
(d) none of the above
Answer. (b)
17. Atoms which have different atomic
numbers, different mass numbers but the same number of neutrons are called
_______
(a) isotopes
(b) isobars
(c) isotones
(d) isomers
Answer. (c)
18. Which of the following statement is
true for 14C6, 15 N7 and 16O8 ?
(a) they have equal number of protons
(b) they have equal number of electrons
(c) they have equal number of neutrons
(d) they have equal mass number
Answer. (c)
19. Which of the following pairs
represents isotones?
(a) 1H1 and 2H1
(b) 40Ar18 and 40K19
(c) 14C6 and 16O8
(d) 22Ne10 and 23Na11
Answer. (c)
20. Which of the following pairs
represents isobars?
(a) 17O8 and 16O8
(b) 40K19 and 40Ca20
(c) 15N7 and 16O8
(d) 235U92 and 238U92
Answer. (b)
21. An isotone of 14C6is
_______
(a) 16O8
(b) 13C6
(c) 17O8
(d) 16N7
Answer. (a)
22. Which of the following is
isoelectronic with Cl–1?
(a) S2–
(b) P3–
(c) K+
(d) All
Answer. (d)
23. Two nuclei A and B are isotonic with
mass numbers 15 and 16 respectively. If A contains 7 protons, then the number
of protons in B would be _______
(a) 7
(b) 8
(c) 9
(d) 10
Answer. (b)
24. 76Ge32 is
isotonic with _______
(a) 77 Ge32
(b) 78As 33
(c) 78 Ge32
(d) 77 As33
Answer. (d)
25. Which of the following atoms
contains the largest number of neutrons?
(a) 210Bi 83
(b) 208Bi 83
(c) 209 Pb84
(d) 208Pb84
Answer. (a)
Reference: Essentials of Physical
Chemistry /Arun Bahl, B.S Bahl and G.D. Tuli / multicolour edition. .
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