Table of Contents
STRUCTURE OF ATOM CLASS 9 MCQ
21.Elements with valency 1 are:
a)Always metals
b)Either metals or non-metals
c)Always metalloids
d)Always non-metals
Ans.Either metals or non-metals
22.The first model of an atom was given by:
a)N. Bohar
b)E. Goldstein
c)Rutherford
d)J.J. Thomson
Ans. J.J Thomson
23.An atom with 3 protons and 4 neutrons will have a valency of:
a)3
b)7
c)1
d)4
Ans. 1
24.The electron distribution in an aluminium atom is:
a)2, 8, 3
b)2, 8, 2
c)8, 2, 3
d)2, 3, 8
Ans. 2, 8, 3
25.Which of the following statements is always correct?
a)An atom has equal number of electrons and protons.
b)An atom has equal number of electrons and neutrons.
c)An atom has equal number of protons and neutrons.
d)An atom has equal number of electrons, protons and neutrons.
Ans. An atom has equal number of electrons and protons.
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26.Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order:
i.Rutherford’s atomic model
ii.Thomson’s atomic model
iii.Bohr’s atomic model
a)(ii)and (ii) and (iii)
b)(ii), (iii) and (i)
c)(ii), (i) and (iii)
d)(iii), (ii) and (i)
Ans. (ii), (i) and (iii)
27.Is it possible for the atom of an element to have one electron, one proton and no neutron?
a)Yes, hydrogen
b)No, hydrogen
c)Yes, electron
d)No, electron
Ans. No hydrogen
28.The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?
a)Atomic number
b)Nucleus
c)Mass number
d)Isobars
Ans. Isobars
29.Rutherford’s alpha particle scattering experiment led to the discovery of the
a)Nucleus
b)Atomic number
c)Mass number
d)All of the above
Ans. Nucleus
30.An element X has a mass number 4 and atomic number 2. Write the valency of the element.
a)1
b)3
c)5
d)0
Ans. 0
ALSO VISIT : ATOMS AND MOLECULES CLASS 9 MCQ
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