CBSE Questions for Class 9 Chemistry Structure Of The Atom Quiz 14 - MCQExams.com

If the atomic number of an atom is $$17$$ and the mass number is $$35$$ then the number of neutrons will be
  • $$35$$
  • $$17$$
  • $$18$$
  • $$52$$
Rutherford's $$\alpha-$$particle scattering experiment discovered
  • Electron
  • Proton
  • Atomic nucleus
  • Neutron
Which type of radiations were used in Rutherford's experiment ?
  • $$\alpha$$
  • $$\beta$$
  • $$\gamma$$
  • $$\lambda$$
In $$\alpha$$-particle scattering experiment, one out of every 12000 particles appeared to rebound. This unexpected result was discovered by which scientist?
  • Willard
  • Roentgen
  • Chadwick
  • Rutherford
According to Rutherford's suggestion how many times smaller should be the atomic nucleus than the total area of an atom?
  • $$10^{15}$$
  • $$10^{10}$$
  • $$10^{8}$$
  • $$10^{5}$$
Which sub-atomic particles revolve around the nucleus?
  • Protons
  • Neutrons
  • Electrons
  • None of these
The discovery of nucleus was done by
  • J. J. Thomson
  • Chadwick
  • Rutherford
  • Moseley
State True or False:
No current flows through the discharge tube when the pressure of the gas inside is one atmosphere.
  • True
  • False
Which of the following observations from Rutherfords experiment disprove Thomsons proposal that the atom is a positively charged sphere?
Observation IMost of the fast-moving $$\alpha$$- particles passed straight through the gold foil.
Observation IISome of the $$\alpha$$- particles were deflected by the foil by small angles.
Observation IIIOne out of every $$12000$$ particles appeared to rebound.
  • Observation I only
  • Observation III only
  • Observations II and III
  • None of these observations disprove Thomsons model
State True or False:
The mass of a proton and a neutron is taken as one unit each.
  • True
  • False
Which of the following atom has no neutron in its nucleus ?
  • Helium
  • Lithium
  • Protium
  • Tritium
Positively charged radiation was discovered by?
  • Chadwick
  • Thomson
  • Goldstein
  • Bohr
An atom as a whole is electrically neutral because the number of protons is equal to the number of electrons. Is the given statement true?
  • Yes
  • No
  • Depends on the type of atom
  • Cannot be determined
The atomic mass of an atom is the sum of the atom's neutrons and protons.
  • True
  • False
In Rutherford's experiment, a thin gold foil was bombarded with alpha particles. If 'Thomson's Plum-Pudding' model of the atom was applicable, then what should have happened?
  • All the alpha particles would have been deflected by the foil.
  • All the alpha particles should have bounced straight back from the foil.
  • Alpha particles should have passed through the foil with little or no deflection.
  • Alpha particles should have become embedded in the foil.
In Bohr's model of an atom :
  • Electrons revolve around the nucleus in circular orbits.
  • These circular orbits or shells are stationary.
  • Each shell in associated with a definite amount of energy.
  • All shells have equal energy level.
Which of the following statements is NOT true?
  • The particles which are present in an atom are known as sub-atomic particles
  • The particles which are present in a nucleus are known as nucleons.
  • An alpha particle is a doubly ionized helium nucleus.
  • The mass of an electron is $$1.06\times 10^{-19}g$$
In a particular set-up, the Rutherford alpha ray scattering experiment using thin gold foil, $$\displaystyle N(\theta )$$ is found to be $$x$$. If a platinum foil of double thickness is used instead, $$\displaystyle N(\theta )$$ would be:
  • $$0.67x$$
  • $$1.67 x$$
  • $$2.67 x$$
  • $$2 x$$
Rutherford's alpha particle scattering experiment established that:
  • protons are not evenly distributed throughout an atom
  • electrons have a negative charge
  • electrons have a positive charge
  • atoms are made of protons, neutrons, and electrons
The density of nucleus is about _______ times the density of atom.
  • $$10^{-14}$$
  • $$10^{-12}$$
  • $$10^{-8}$$
  • $$10^{10}$$
The mass of an atom is concentrated inside the ............. of an atom.
  • nucleus
  • neutron
  • proton
  • electron
The ratio of the energy of photon of $$2000 A^0$$ wavelength to that of $$4000 A^0$$ wavelength is:
  • 1 : 4
  • 4 : 1
  • 1 : 2
  • 2 : 1
Which of the following doesn't have charge?
  • Proton
  • Neutron
  • Electron
  • Isotope
  • Ion
Statement I : $$\displaystyle ^{ 12 }{ C }\ $$ is an isotope of  $$\displaystyle ^{ 14 }{ C }\ $$.
Statement II: The nuclei of both atoms have the same number of neutrons.
  • true, false
  • false, true
  • false, false
  • true, true, correct explanation
According to Rutherford's model of an atom:
  • There is a positively charged centre in an atom called the nucleus.
  • Electrons never lose or gain energy.
  • The electrons revolve around the nucleus in circular paths.
  • Electrons do not move at all.
If Rutherford would have used $$\beta $$-particles instead of $$\alpha $$-particles in his Goldleaf experiment which of the following observation would definitely not have been made?
  • Get condensed or concentrated
  • Majority of $$\beta $$-particles passing unperfected through the foil
  • Very few $$\alpha $$-particles getting absorbed
  • Wave nature of electron
If one were to apply Bohr's model to a particle of mass 'm' and charge 'q' moving in a plane under the influence of a magnetic field 'B', the energy of the charged particles in the $$n^{th}$$ level will be:
  • n$$(\dfrac{hqB}{8\pi m})$$
  • n$$(\dfrac{hqB}{4\pi m})$$
  • n$$(\dfrac{hqB}{2\pi m})$$
  • n$$(\dfrac{hqB}{\pi m})$$
One Bohr magneton is equal to ____________ $${ AM }^{ 2 }$$.
  • $$4.8\times { 10 }^{ -10 }eSu$$
  • $$1.6\times { 10 }^{ -19 }eSu$$
  • $$4.8\times { 10 }^{ -10 }\ eSu\ \& 1.6\times { 1 0}^{ -19 } \ eSu$$
  • $$9.27\times { 10 }^{ -24 }$$
Which of the following concept was considered in Rutherford's atomic model?
  • The electrical neutrality of atom
  • Electrons revolve around nucleus at a very high speed
  • Existence of nuclear forces of attraction on the electrons.
  • All of the above
Which of the following are isotopes?
(i) Atom, whose nucleus contains 20p+15n
(ii) Atom whose nucleus contains 20p+17n
(iii) Atom, whose nucleus contains 18p+22n
(iv) Atom, whose nucleus contains 18p+21n
  • (i) and (iii)
  • (i) and (ii)
  • (ii) and (iii)
  • (ii) and (iv)
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