STRUCTURE OF ATOM Test

STRUCTURE OF ATOM

This is STRUCTURE OF ATOM Test-02 for CBSE class 12 Chemistry.. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Which of these is not part of Bohr’s theory for hydrogen atom?
  • A
    The most important property associated with the electron, is the energy of its stationary state. It is given by the expression ${E_n} = {R_H}\left( {\frac{1}{{{n^2}}}} \right)$
  • B
    The radii of the stationary states are expressed as : $r_n$ = $n^2$ $a_0$ (2.12) where $a_0$ = 52.9 pm. As n increases the value of r will increase. In other words the electron will be present away from the nucleus
  • C
    The stationary states for electron are numbered n = 1,2,3.......... These integral numbers are known as Principal quantum numbers.
  • D
    Radiation should exhibit both particle and wavelike properties $\lambda = \;\frac{h}{{mv}}$
    Correct
2
According to the Heisenberg uncertainty principle, in dealing with milligram-sized or heavier objects,
  • A
    the associated uncertainties are hardly of any real consequence
    Correct
  • B
    there are no uncertainties at all
  • C
    the associated uncertainties are very important
  • D
    the associated uncertainties are unacceptable
3
Quantum mechanics is a theoretical science that deals with the study of the
  • A
    motions of the macroscopic objects that have only particle like properties
  • B
    motions of the macroscopic objects that have both observable wave like and particle like properties
  • C
    motions of the microscopic objects that have only particle like properties
  • D
    motions of the microscopic objects that have both observable wave like and particle like properties
    Correct
4
According to quantum theoretical model of an atom each orbital is designated by three quantum numbers labelled as n, l and ml. These are referred to respectively as
  • A
    Principal quantum number, Azimuthal quantum number or orbital angular momentum and Magnetic orbital quantum number.
    Correct
  • B
    Azimuthal quantum number or orbital angular momentum, Principal quantum number, and Magnetic orbital quantum number.
  • C
    Principal quantum number, Azimuthal quantum number or orbital angular momentum and spin quantum number
  • D
    Azimuthal quantum number or orbital angular momentum, Principal quantum number, and spin quantum number.
5
According to quantum theoretical model of an atom each orbital is designated by three quantum numbers labelled as n, l and ml. The values these can take are
  • A
    n = 1, 2, 3..; l = 0, 1,.. n-1; ml = -l,-l+1, ..0,1..l-1, l
    Correct
  • B
    n = 1,2,3.; l = 0,1,..n; ml = -l,-l+1, ..0,1
  • C
    n = 1,2,3..; l = 0,1,..n; ml = -l,-l+1, ..0,1..l-1, l
  • D
    n = 1,2,3..; l = 0,1,..n-1; ml = 0,1..l-1, l
6
spin quantum number with two spin states of the electron represented by two arrows, ↑ (spin up) and ↓ (spin down) was introduced to account for
  • A
    the splitting of emission lines in a magnetic field
  • B
    anomalous Zeeman effect or the splitting of emission lines into more lines than given by magnetic quantum number
    Correct
  • C
    to account for uncertainty in electron states
  • D
    the splitting of emission lines in an electric field
7
According to quantum mechanics $ψ^2$(r) the wave function squared gives
  • A
    probability density of finding a proton
  • B
    probability of finding a neutron
  • C
    probability density of finding an electron
    Correct
  • D
    probability of finding an electron
8
Due to the presence of electrons in the inner shells, the electron in the outer shell will not experience the full positive charge of the nucleus (Ze). This is known as
  • A
    charge stealing by inner shell electrons from the outer shell electrons
  • B
    charge stealing by outer shell electrons from the inner shell electrons
  • C
    shielding of the inner shell electrons from the nucleus by the outer shell electrons
  • D
    shielding of the outer shell electrons from the nucleus by the inner shell electrons
    Correct
9
The Aufbau principle states : In the ground state of the atoms, the orbitals are filled in order of
  • A
    their decreasing radius
  • B
    their increasing radius
  • C
    their increasing energies
    Correct
  • D
    their decreasing energies
10
According to Pauli’s exclusion principle
  • A
    Any two electrons in an atom can have the same set of four quantum numbers
  • B
    No two electrons in an atom can have the same set of four quantum numbers
    Correct
  • C
    All electrons in an atom can have the same spin numbers
  • D
    Any two electrons in an atom can have the same spin numbers
11
Daltons atomic theory could not explain one of the following
  • A
    Law of multiple Proportions,
  • B
    Law of constant composition
  • C
    Law of conservation of mass
  • D
    Discovery of sub-atomic particles
    Correct
12
Oil drop experiment is for determining the
  • A
    deviation of the electron.
  • B
    charge on the electrons
    Correct
  • C
    number of electrons
  • D
    mass of the electron
13
How many neutrons and protons are there in the ${}_6^{13}C$ nucleus?
  • A
    7, 6
    Correct
  • B
    8, 5
  • C
    8, 6
  • D
    0, 13
14
Cathode rays are discharged under one of the following conditions:
  • A
    when a certain type of gas is used
  • B
    only when the rays become negatively charged
  • C
    when a certain type of electrode is used
  • D
    at very low pressure and high voltage
    Correct
15
One of the following scientists was the first to discover electron based on its charge
  • A
    James Chadwick
  • B
    Michael Faraday
    Correct
  • C
    J.J. Thomson
  • D
    Ernest Rutherford