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TEXTBOOK (MCQs)

 

Q(1). For which species Bohr’s theory does not apply

(a) H                             (b)
He+

(c) Li2+                          (d)
Be

 

Correct Answer: (d) Be

Explanation:

Bohr’s theory is
successfully applied to mono-electron system e.g. H, He+, Li2+.
However, it fails for multi-electron systems. e.g. Be, since it contains 4
electrons.


Q(2). From the discharge tube experiment, it is concluded
that

(a) Mass of
proton is in fraction.

(b) Matter
contained electrons.

(c) Nucleus contains
positive change.

(d) Positive
rays are heavier than protons.

 

Correct Answer: (b) Matter contained
electrons

Explanation:

In discharge tube
experiments, cathode rays were produced. These were proved to be electrons.


Q(3). When an electron of charge ‘e’ and mass ‘m’ moves
with velocity ‘v’ about the nuclear change Ze in the circular orbit of radius
‘r’, the P.E of electron is given by

(a) Ze2/r                       (b)
– Ze2/r

(c) Ze2/r2                      (d)
mv2/r

 

Correct Answer: (b) –Ze2/r

Explanation:

The P.E. of electron is
obtained from Columb’s law. Thus it is given as


Q(4). Which of following tells about shells of an atom?

(a) Principal
quantum number, n

(b) Azimuthal
quantum number, l

(c) Magnetic
quantum number, m

(d) Spin
quantum number, s

 

Correct Answer: (d) Spin quantum
number, s

Explanation:

Three quantum numbers are
obtained by solving Schrodinger’s wave equation:

1. Principal
quantum number (n)

2. Azimuthal
quantum number (
)

3. Magnetic
quantum number (m)


Q(5). Electronic configuration of species M2+
is 1s2  2s2  2p6  3s2  3p6 
3d6 and its atomic weight is 56 number of neutrons in the nucleus of
species M is

(a) 20                           (b)
26

(c) 28                           (d)
30

 

Correct Answer: (d) 30

Explanation:

M2+ = 1s2  2s2
 2p6  3s2  3p6  3d6

When two electron are added
to M2+, it becomes M. the electronic configuration of M is

M = 1s2  2s2 
2p6  3s2  3p6  3d8

Thus the atomic number of M
is 26 and its atomic mass is 56.

Number of neutrons = 56-26
= 30


Q(6). The energy of an electromagnetic radiation is 3 x 10-12
ergs. What is its wave length in Nano-meters?

(a) 400                        (b)
228.3

(c) 3000                      (d)
662.5

 

Correct Answer: (d) 662.5

Explanation:

Since   107 erg
= 1 J

So        3 x 10-12
erg = 3 x 10‑ J

 

 

 

 

            Since
10-9m = 1nm


Q(7). Which of the following configuration is not correct
according to Hund’s rule?

(a)         (b)

(c)      (d)

 

Correct Answer:        (b)

Explanation:

According to Hund’s Rule:

If orbitals of same energy
are available then electrons will go in separate orbitals with same spin,
rather than in same orbital with opposite spin. The correct electronic
configuration is


Q(8). Which one of the following statement is not correct?

(a) Rydberg’s
constant and wave number have same unit.

(b) Lyman
series of hydrogen spectrum occurs in the ultraviolet region.

(c) The
angular movement of the electron in the ground state of hydrogen atom is equal
to

(d) The
radius of first Bohr orbit of hydrogen atom is 2.116 x 10-8cm.

 

Correct Answer: (d) The radius of
first Bohr orbit of hydrogen atom is 2.116 x 10-8cm.

Explanation:

Options (a), (b) and (c)
are correct.

Option (d) is not correct,
since

           

          When n = 1

           


Q(9). Which one of the following is not isoelectronic
pair?

(a) Mg2+, Be2+               (b)
N3-, O2-

(c) N3-, F                     (d)
F, Ai3+

 

Correct
Answer:
(d)
Mg2+, Be2+

Explanation:

The species which contain
same number of electrons are called isoelectronic species.

(a) Mg2+
contains 10 electrons but Be2+ contains 2 electrons (not
isoelectronic).

(b) Both N3-
and O2- contain 10 electrons each (isoelectronic)

(c) Both N3+
and F contain 10 electrons each (isoelectronic)

(d) Both F
and Ai3+ contain 10 electrons each (isoelectronic)


Q(10). The third line in Balmer series corresponds to an
electronic transfer between which Bohr’s orbits in hydrogen.

(a)                       (b)

(c)                       (d)

 

Correct
Answer:
(d)

Explanation:

Third line in Balmer series
appears when electron jumps from n=5 to n=2 orbit in hydrogen.


 

 

IMPORTANT (MCQs) FOR
ECAT & MCAT

 

Q(1). In atomic particles

(a) Mass of
neutron is almost equal to mass of electron

(b) e/m of a
proton is almost equal to e/m of electron

(c) mass of
proton is almost equal to mass of electron

(d) charge
of proton is almost equal to charge of electron

 

Correct Answer: (d) correct


Q(2). In discharge tube experiment the pressure of gas was
measured at

(a) 760 torr                 (b)
0.1 torr

(c) 0.01 torr                (d)
10 torr

 

Correct Answer: (d) correct


Q(3). The charge (in coulombs) of one gram of electron is

(a) 1.7588 x 10-11          (b)
1.7588 x 1011

(c) 1.602 x 10-19           (d)
1.7588 x 108

 

Correct Answer: (d) correct


Q(4). The nature of cathode rays in discharge tube

(a) Depends
on the nature of gas taken in the discharge tube

(b) Depends
upon the nature of cathode in discharge tube

(c) Is
independent of the nature of the gas in discharge tube

(d) Depends
upon the nature of anode in the discharge tube

 

Correct Answer: (d) correct


Q(5). If the e/m value of electron is 1.7588 x 1011
coulombs kg-1, then what would be the mass of electron in grams
(charge on electron is 1.6022 x 10-19 coulombs)?

(a) 9.1095 x 1031g       
(b) 91.095 x 10-31g

(c) 9.1095 x 10-28g     
(d) 0.919095 x 10-33g

 

Correct Answer: (d) correct


Q(6). Negative charge on cathode rays was established by

(a) William Crook       (b)
J Perin

(c) J.J. Thomson          (d)
Hittrof

 

Correct Answer: (d) correct


Q(7). Cathode rays cause a chemical change because they
have __________ effect.

(a) Oxidizing               (b)
Conducting

(c) Reducing               (d)
Diffusing

 

Correct Answer: (d) correct


Q(8). Mass of electron is

(a) 9.1095 x 1031kg      (b)
9.1095 x 10-31kg

(c) 9.1095 x 10-27kg
    (d) 9.1095 x 10-31g

 

Correct
Answer:
(d) correct

Q(9). The charge on electron was determined by

(a) Bohr                       (b)
Rutherford

(c) Millikan                  (d)
J.J. Thomson

 

Correct
Answer:
(d) correct

Q(10). The e/m value for the positive rays is maximum for

(a) Hydrogen              (b)
Helium

(c) Nitrogen                (d)
Oxygen

 

Correct
Answer:
(d)
correct

Q(11). The e/m of positive rays is __________ than that of
cathode rays

(a) equal to                 (b)
lesser

(c) greater                   (d)
not known

 

Correct
Answer:
(d)
correct

Q(12). Positive rays were discovered by

(a) J.J Thomson           (b)
Rutherford

(c) William Crooks      (d)
Eugene Gold Stein

 

Correct
Answer:
(d)
correct

Q(13). The positive particle produced in the discharge tube
from Hydrogen gas was named Proton by

(a) Millikan                  (b)
Goldstein

(c) Rutherford             (d)
Chadwick

 

Correct
Answer:
(d) correct

Q(14). The nature of anode rays depend on

(a) The
nature of the electrode

(b) The
nature of the residual gas

(c) The
nature of the discharge tube

(d) All of
above

 

Correct
Answer:
        (d) correct

Q(15). The nature of positive rays depends on

(a) The
nature of electrode

(b) the
nature of the discharge tube

(c) the
nature of the residual gas

(d) All of
the above

 

Correct
Answer:
        (d) correct

Q(16). Which of the following statement regarding cathode
ray is correct

(a) Cathode
rays can ionize gas

(b) Cathode
rays can possess momentum

(c) Cathode
rays can cause chemical changes

(d) All of
these

 

Correct
Answer:
        (d) correct

Q(17). Neutron was discovered by Chadwick in

(a) 1935                        (b)
1930

(c) 1932                        (d)
1934

 

Correct
Answer:
        (d) correct

Q(18). Bombardment of  on Beryllium (Be) atom emits neutron and this
process is called

(a) Natural
radioactivity

(b) Artificial
radioactivity

(c) Paull
exclusion principle

(d) Hund’s
rule

 

Correct
Answer:
        (d) correct

Q(19). . What is “x”?

(a) neutron                 (b)
proton

(c) Beta rays                (d)
gamma rays

 

Correct
Answer:
        (d) correct

Q(20). In atomic particles

(a) Mass of
neutron is almost equal to mass of electron

(b) e/m of a
proton is almost equal to e/m of electron

(c) Mass of
proton is almost equal to mass of electron

(d) Charge
of proton is almost equal to charge of electron

 

Correct
Answer:
        (d) correct

Q(21). Rutherford’s model of atom failed because

(a) The atom
did not have a nucleus and electron

(b) It did
not account for the attraction between proton and neutrons

(c) It did
not account for the stability of the atom

(d) There is
actually no space between the nucleus and the electrons

 

Correct
Answer:
        (d) correct

Q(22). Angstrom is the unit of

(a) time                       (b)
length

(c) Mass                      (d)
Frequency

 

Correct
Answer:
        (d) correct

Q(23). Properties of waves are

(a) Wave length          (b)
Wave number

(c) Frequency              (d)
all

 

Correct
Answer:
        (d) correct

Q(24). The value of Plank’s constant is

(a) 6.62 x 10-34
J.s        (b) 6.62 x 10-27 J.s

(c) 6.62 x 10-21
J.s        (d) 6.62 x 10-31 J.s

 

Correct
Answer:
        (d) correct

Q(25). The wave number of the light emitted by a certain
source is 2 x 106 m. The wavelength of the light will be

(a) 500nm                   (b)
500m

(c) 200nm                   (d)
5 x 107m

 

Correct
Answer:
        (d) correct

Q(26). The velocity of photon is

(a) Independent
of its wavelength

(b) Depends
on its wavelength

(c) Equal to
square of its amplitude

(d) Depends
on its amplitude

 

Correct
Answer:
        (d) correct

Q(27). Number of wave per unit length is called

(a)                              (b)

(c)                              (d) E

 

Correct
Answer:
        (d) correct

Q(28). The electron present in a particular orbit
__________ energy

(a) Releases                 (b)
Does not radiate

(c) Absorbs                 (d)
None of these

 

Correct
Answer:
        (d) correct

Q(29). Splitting of spectral lines in closely spaced lines
in presence of magnetic field is called

(a) Stark Effect             
(b) Zeeman Effect

(c) Photoelectric Effect (d)
Compton Effect

 

Correct
Answer:
        (d) correct

Q(30). Energy required to remove an electron from the
outermost shell of its isolated gaseous atom in the ground state is

(a) Electron affinity    (b)
Lattice Energy

(c) Ionization energy  (d) Crystal
Energy

 

Correct
Answer:
        (d) correct

Q(31). The radius of first orbit of hydrogen atom is

(a)                   (b)

(c)                   (d)

 

Correct
Answer:
        (d) correct

Q(32). Radius of 3rd orbit of H-atom is

(a)                      (b)

(c)                      (d)

 

Correct
Answer:
        (d) correct

Q(33). Lines of Paschen series are produced when electrons
jump from higher orbits to __________ Orbits.

(a) 1st                            (b)
2nd

(c) 3rd                           (d)
4th

 

Correct
Answer:
        (d) correct

Q(34). Value of the Redberg’s constant is

(a) 1.7904 x 107m-1      (b)
1.9768 x 102m-1

(c) 1.09678 x 107m-1       (d)
1.6 x 107m-1

 

Correct
Answer:
        (d) correct

Q(35). Bohr’s model of atom is contradicted by

(a) Planck
quantum theory

(b) Pauli’s
exclusion principle

(c) Heisenberg’s
uncertainty principle

(d) All of
the above

 

Correct
Answer:
        (d) correct

Q(36). Splitting of spectral lines when atoms are subjected
to strong electric field is called

(a) Zeeman effect                   (b)
Stark effect

(c) Photoelectric effect          (d)
Compton effect

 

Correct
Answer:
        (d) correct

Q(37). In the ground state of an atom, the electron is
present

(a) In the
nucleus

(b) In the
second shell

(c) Nearest
to the nucleus

(d) Farthest
from the nucleus

 

Correct
Answer:
        (d) correct

Q(38). The extent of bending of a light ray after passing
through prism depends upon

(a) Wavelength
of photons

(b) Wave
number of photons

(c) Energy
of photons

(d) Frequency
of photons

 

Correct
Answer:
        (d) correct

Q(39). The velocity of photon is

(a) Equal to
square of its amplitude

(b) Independent
of its wavelength

(c) Equal to
its wave number

(d) Equal to
velocity of light

 

Correct
Answer:
        (d) correct

Q(40). Balmer series in hydrogen spectrum lies in the
region

(a) Ultraviolet             (b)
visible

(c) infrared                  (d)
microwave

 

Correct
Answer:
        (d) correct

Q(41). Lyman series lies in

(a) UV region  (b) visible
region

(c) IR region    (d) Microwave
region

 

Correct
Answer:
        (d) correct

Q(42). The limiting line of Balmer Series lies in the
region

(a) visible                    (b)
U.V

(c) Near I.R.                 (d)
Far I.R.

 

Correct
Answer:
        (d) correct

Q(43). Which rays are electromagnetic radiations and travel
with the velocity of light

(a) Canal rays              (b)
Alpha rays

(c) Beta rays                (d)
Gamma rays

 

Correct
Answer:
        (d) correct

Q(44). X-rays were discovered by

(a) Moseley                 (b)
Roentgen

(c) Rutherford             (d)
de-Broglie

 

Correct
Answer:
        (d) correct

Q(45). Which of the following is the Moseley’s equation?

(a)

(b)

(c)                   

(d)

 

Correct
Answer:
        (d) correct

Q(46). Which one element will produce X-rays of high
energy?

(a) Al                            (b)
Cu

(c) Zn                           (d)
U

 

Correct
Answer:
        (d) correct

Q(47). The position of a fast moving electron cannot be
determined precisely. It is because the photon used to determine position have

(a) Longer
wavelength

(b) Higher
momentum

(c) Lesser
energy

(d) Lesser
momentum

 

Correct Answer:        (d) correct

Q(48). De-Broglie’s equation is characterized by

(a)            (b)

(c)            (d)

 

Correct
Answer:
        (d) correct

Q(49). Which particle has greater wavelength?

(a) electron                 (b)
proton

(c) neutron                 (d)

 

Correct
Answer:
        (d) correct

Q(50). Which quantum number helps is study the orientation
of an orbital in space?

(a) Principal
quantum Number

(b) Spin
quantum Number

(c) Magnetic
quantum Number

(d) Azimuthal
quantum Number

 

Correct
Answer:
        (d) correct

Q(51). With increase in the value of Principal Quantum
Number ‘n’, the shape of the s-orbitals remains the same although their sizes

(a) Decrease

(b) Increase

(c) Remain
the same

(d) May or
may not remain the same

 

Correct
Answer:
        (d) correct

Q(52). Quantum number values for 3p orbitals are

(a)            (b)

(c)            (d)

 

Correct
Answer:
        (d) correct

Q(53). An orbital which is spherical and symmetrical is

(a) s-orbital                (b)
p-orbital

(c) d-orbital                (d)
f-orbital

 

Correct
Answer:
        (d) correct

Q(54). Quantum number values for 2p orbitals are?

(a)            (b)

(c)            (d)

 

Correct
Answer:
        (d) correct

Q(55). Orbitals having same energy are called

(a) hybrid orbitals        
(b) valence orbitals

(c) degenerate orbitals  (d)
d-orbitals

 

Correct
Answer:
        (d) correct

Q(56). When 6d orbital is complete, the entering electron
goes into

(a) 7f                            (b)
7s

(c) 7p                           (d)
7d

 

Correct
Answer:
        (d) correct

Q(57). Which pair of transition elements shows abnormal
electronic configuration?

(a) Sc and Zn               (b)
Cu and Sc

(c) Zn and Cu               (d)
Cu and Cr

 

Correct
Answer:
        (d) correct

Q(58). Correct order of energy in the given subshells is

(a)   
5s > 3d > 3p > 4s

(b)   
5s > 3d > 4s > 3p

(c)    
3p > 3d > 5s > 4s

(d)   
3p > 3d > 4s > 5s

 

Correct
Answer:
        (d) correct

Q(59). Number of electrons in the outermost shell of
chloride ion (Cl) is

(a) 17                            (b)
3

(c) 1                              (d)
8

 

Correct
Answer:
        (d) correct

Q(60). The relative energies of 4s, 4p and 3d orbitals are
in the order

(a) 3d < 4p < 4s           (b)
4s < 3d < 4p

(c) 4p < 4s < 3d           (d)
4p < 3d < 4s

 

Correct
Answer:
        (d) correct

Q(61). Electronic configuration of Manganese (Mn) is

(a) [Ar] 4s2 3d5             (b)
[Ar] 4s2 3d4

(c) [Ar] 4s1 3d            (d)
[Ar] 4s2 3d7

 

Correct
Answer:
        (d) correct

Q(62). Which one of the following pairs has the same
electronic configuration as possessed by Neon (Ne-10)

(a) Na+, Cl–                           (b)
K+, Cl

(c) Na+, Mg+                 (d)
Na+, F

 

Correct
Answer:
        (d) correct

Q(63). There are four orbitals s, p, d and f. Which order
is correct with respect to the increasing energy of the orbitals?

(a) 4s <
4p < 4d < 4f

(b) 4p <
4s < 4f < 4d

(c) 4s <
4f < 4p < 4d

(d) 4f <
4s < 4d < 4p

 

Correct
Answer:
        (d) correct

Q(64). Electronic configuration of Gold [Au79] is

(a) [Xe] 4f14,
5d10, 6s1   (b) [Xe] 4f10, 5d10, 6s2

(c) [Xe] 4f14,
5d9, 6s2    (d) [Xe] 4f14, 5d10, 6s2

 

Correct
Answer:
        (d) correct

Q(65). Number of neutron in 30Zn66

(a) 30                           (b)
35

(c) 38                           (d)
36

 

Correct
Answer:
        (d) correct

Q(66). The anomalous electronic configuration shown by
chromium and copper among 3d series of elements is due to

(a) Colour
of ions of these metals

(b) Variable
oxidation state of metals

(c) Stability
associated with this configuration

(d) Complex
formation tendency of metals

 

Correct
Answer:
        (d) correct

Q(67). Maximum number of electrons in an orbital is

(a) 6                             (b)
10

(c) 14                            (d)
2

 

Correct
Answer:
        (d) correct

Q(68). The electronic configuration of an atom is 1s2
2s2 2p4. The number of unpaired electrons in this atom is

(a) 0                             (b)
2

(c) 4                             (d)
6

 

Correct
Answer:
        (d) correct

Q(69). After filling of 4f, the entering electron goes into

(a) 5d                           (b)
6p

(c) 6s                           (d)
4d

 

Correct
Answer:
        (d) correct

Q(70). The number of neutron present in?

(a) 39                           (b)
18

(c) 20                           (d)
19

 

Correct
Answer:
        (d) correct

Q(71). When 4s orbital is complete, the electron goes into

(a) 4p orbital               (b)
3d

(c) 4d                           (d)
4f

 

Correct
Answer:
        (d) correct

Q(72). The element which has maximum number of unpaired
electrons is

(a) Cr24                         (b)
Ca20

(c) Fe26                         (d)
Cu29

 

Correct
Answer:
        (d) correct

Q(73). In which orbital electrons go after 6d?

(a) 7s                            (b)
7p

(c) 3s                            (d)
6f

 

Correct
Answer:
        (d) correct

Q(74). Which of the electronic configuration of nitrogen is
correct?

(a) 1s2,
2s2, 2px1, 2py1, 2pz1

(b) 1s2,
2s2, 2px2, 2py1, 2pz1

(c) 1s2,
2s2, 2px2, 2py2, 2pz2

(d) 1s2,
2s2, 2px2, 2py2, 2pz1

 

Correct
Answer:
        (d)
correct

Q(75). Which of the following electronic configurations
represents an element that forms simple ion with a charge of -3?

(a) 1s2,
2s2, 2p6, 3s2, 3p1

(b) 1s2,
2s2, 2p6, 3s2, 3p3

(c) 1s2,
2s2, 2p6, 3s2, 3p6, 3d1,
4s2

(d) 1s2,
2s2, 2p6, 3s2, 3p6

 

Correct
Answer:
        (d) correct

Q(76). The correct electronic configuration of 24Cr
is

(a) 1s2,
2s2, 2p6, 3s2, 3p6, 4s1,
3d5

(b) 1s2,
2s2, 2p6, 3s2, 3p6, 4s2,
3d4

(c) 1s2,
2s2, 2p6, 3s2, 3p6, 3d6

(d) 1s2,
2s2, 2p6, 3s2, 3p6, 4f6

 

Correct
Answer:
        (d) correct

Q(77). Which two elements are isotopes?

(a)         (b)

(c)         (d)

 

Correct
Answer:
        (d) correct

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