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NEET Chemistry MCQ
Structure Of Atom Mcq Neet Chemistry
Quiz 9
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Q.1
The first emission line in the atomic spectrum of hydrogen in the Balmer series appears at ... [ pb. PMT 1996]
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
First line appears for jump n=3 to n=2 for whichAnswer: (d)
Q.2
Which of the following statements is incorrect? [ AMU 1997]
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a) Cathode rays carry negative charge
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b) frequency of X-ray is higher than that of microwaves
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c)Unit for wave number is m-1
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d)Threshold frequency is the same for all metals
Explanation
Threshold frequency is different for different metalsAnswer: (d)
Q.3
Number of nodal plane 'd' orbital has .... [ KCET 1996]
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a) 1
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b) 2
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c)3
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d)0
Explanation
All d-orbitals have two nodal plane . Spherical nodal plane depend on the value of 'n' and 'l' Answer:(c)
Q.4
The charge of the atom having 17 protons, 18 neutrons and 18 electrons is [ KCET 1994]
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a) +1
0%
b) -1
0%
c) -2
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d) Zero
Explanation
One electron is more than protons Answer: (b)
Q.5
The maximum number of electrons in an atom with l=2 and n=3 is ..[PMP PET 1998]
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a)2
0%
b) 6
0%
c)12
0%
d)10
Explanation
Electrons with l=2 represent d subshell which can have maximum 10 electronsAnswer: (d)
Q.6
When the value of azimuthal quantum number , l=2, value of 'n' will be .... [ CPMT 1995]
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a) 3
0%
b) 4
0%
c)5
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d)any one of these
Explanation
l can take the values from 0 to (n-1) ∴If l=2 then n can not be 1 Answer: (d)
Q.7
The heaviest particle is ....[ DPMT 1994]
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a) Meson
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b) Neutron
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c)Electron
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d)Proton
Explanation
Answer:(b)
Q.8
The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is .... [CPMT 1997]
0%
a) 2
0%
b) 17
0%
c) 37
0%
d) 38
Explanation
Answer: (d)
Q.9
Which of the following is the cause of late discovery of neutron? [ AIIMS 1998]
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a)Neutron is charge less particle
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b) Neutron is highly unstable particle
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c)neutron in the nucleus moves very fast
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d)All of these
Explanation
Answer: (a)
Q.10
What do you mean by degenerate orbitals? ... [ CBSE PMT 19996]
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a) Orbitals having equal energy
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b) Orbitals having equal wave function
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c)Orbital having equal energy but different wave function
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d)Orbitals having equal energy and equal wave function
Explanation
Answer:(a)
Q.11
Consider the following ionsNi2+Co2+Cr2+Fe3+ Atomic number Cr=24, Fe - 16, Co=27, Ni=28 The correct sequence of the increasing order of the number of unpaired electrons is ....
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a) 1, 2, 3, 4
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b) 4, 2, 3, 1
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c) 1, 3, 2, 4
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d) 3, 4, 2, 1
Explanation
Un paired electrons in Ni2+=2 Co2+=3Cr2+=4 Fe3+=5 Answer: (a)
Q.12
Wavelength associated with electron motion ... [ BHU 1998]
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a)increases with increase in speed of electron
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b) remains same irrespective of speed of electron
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c)decreases with increase of speed of electron
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d)is zero
Explanation
wavelength is given by equationAnswer: (c)
Q.13
Which orbital of carbon can absorb photon but not emit it?{CPMT 1997]
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a) 1s
0%
b) 2s
0%
c)3p
0%
d)2p
Explanation
1s is the lowest energy. It can absorb photon but not emit itAnswer: (a)
Q.14
Atomic weight of an element is not necessarily whole number because... [ DCE 1994]
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a) It contains electrons, protons and neutrons
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b) It contains allotropic forms
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c) atoms are no longer considered indivisible
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d) it contains isotopes
Explanation
Atomic weight is the average value of mass numbers of isotopes Answer: (d)
Q.15
Planck's constant has the same dimensions as that of ... [ AIIMS 1998]
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a)power
0%
b) work
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c)radiation energy
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d)angular momentum
Explanation
angular momentum=nh/2πAnswer: (d)
Q.16
The value of quantum numbers n, l, and m for 5th electron of Born will be
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a) n=1, l=0, m=-1
0%
b) n=2, l=1, m=-1
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c)n=2, l=2, m=-1
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d)n=1, l=2, m=-1
Explanation
E.C. of 5B=1s2, 2s, 2p1Answer: (b)
Q.17
The hydride ion is isoelectric with ..... [ AFMC 1995]
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a) H+
0%
b) He+
0%
c)He
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d)Be
Explanation
Answer:(c)
Q.18
Electron configuration of four metals are given below. Which of the corresponding element would be most paramagnetic? [ AMU 1997]
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a) 1s2, 2s2, 2p6
0%
b) 1s2, 2s2 2p1
0%
c) 1s2, 2s2, 2p5
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d) 1s2, 2s2 2p4
Explanation
option 'd' have three unpaired electrons while remaining have less than 3 unpaired electrons Answer: (d)
Q.19
An electron has magnetic quantum number as -3, what is its principal quantum number
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a)1
0%
b) 2
0%
c)3
0%
d)4
Explanation
l can take the values from 0 to (n - 1)Answer: (d)
Q.20
The electron configuration of 21Sc is ...{BHU 1997]
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a) 1s2 2s2 2p6 2s2 3p64s23d1
0%
b)1s2 2s2 2p6 2s2 3p64s13d2
0%
c)1s2 2s2 2p6 2s2 3p64s03d3
0%
d)1s2 2s2 2p6 2s2 3p64s23d2
Explanation
Answer: (a)
Q.21
Which of the following has maximum number of unpaired electrons? [ IIT 1996]
0%
a) Mg2+
0%
b) Ti3+
0%
c)V3+
0%
d)Fe2+
Explanation
E.C 12Mg=[Ne] 3s2 Ec. Mg2+=[Ne] unpaired electrons zero E.C 22T=[Ar] 4s2 3d2E.C Ti3+=[Ar] 4s1 unpaired 1 electron E.C 23V=[Ar] 4s2 3d3 V3+=[Ar] 4s1 unpaired 1 electron E.C 26V=[Ar] 4s2 3d6 Fe3+=[Ar] 4s1 3d3 unpaired 3 electron Answer:(d)
Q.22
Bohr's radius of Hydrogen atom is ... [ Haryana CEET 1994]
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a) 0.529 × 10-8 m
0%
b) 0.529 ×10-10 m
0%
c) 5.29 ×10-8 m
0%
d) 5.29 × 10-10 m
Explanation
Answer: (b)
Q.23
the electrons identified by quantum numbers n and l (i) n=4, l=1 (ii) n=4, l=0 (iii) n=3 , l=2 (iv) n=3, l=1 can be placed in order of increasing energy, from the lowest to highest, as
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a)(iv) < (ii) < (iii) <(i)
0%
b) (ii) < (iv) < (i) < (iii)
0%
c)(i) < (iii) < (ii) < (iv)
0%
d)(iii) < (i) < (iv) < (ii)
Explanation
energy is more if (n+l) is more , if value for two (n+l) is same then more the value of n more is the energyAnswer: (a)
Q.24
The outer electronic configuration of 3s2 3p5 is possessed by... [ KECT 1997]
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a) O
0%
b) Cl
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c)Br
0%
d)Ar
Explanation
Answer: (b)
Q.25
The paramagnetic character follows the order .... [ CBSE MPT 1997]
0%
a) Mg > Cr > Zn
0%
b) Fe > Zn >Co
0%
c)Cr > Fe > Zn
0%
d)Hg > Mn > Fe
Explanation
Calculate number of unpaired electrons in each Number of unpaired electrons in Cr are 6, 4 in Fe and 0 in Zinc Answer:(c)
Q.26
Bohr's model was modified by ... [ EAMCET 1995]
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a) Sommerfeld
0%
b) Rutherford
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c) Dalton
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d) Pauli
Explanation
Answer: (a)
Q.27
ratio of mass of proton and electron is ... [ BHU 1998]
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a)infinite
0%
b) 1.8 × 10+3
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c)1.8
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d)none of these
Explanation
mp / me=1837=1.8 × 10+3 Answer: (b)
Q.28
Brackett series are produced when the electrons from outer orbits jump to .... [ Pb CET 1997]
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a) 2 nd orbit
0%
b) 3 rd orbit
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c)4 th orbit
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d)5 th orbit
Explanation
Answer: (c)
Q.29
heisenberg's Uncertainty Principle is applicable to ... [ BHU 1994]
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a) atoms only
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b) electrons only
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c)nucleus only
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d)any moving object
Explanation
Answer:(d)
Q.30
An element M has an atomic mass 19 and atomic number 9, its ion is represented by [ IIT 1996]
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a) M+
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b) M2+
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c) M-
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d) M2-
Explanation
atomic number 9 bu accepting one electron it attends the nobel gas configuration thus option(c) Answer: (c)
Q.31
Which of the following has more unpaired d-electrons? [ CBSE PMT 1999]
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a)Zn+
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b) Fe3+
0%
c)Cu3+
0%
d)Cu+
Explanation
Unpaired electrons in Zn2+=0, , Ni3+=3, in Cu+=0 and Fe2+=4Answer: (c)
Q.32
The energy of an electron in the first Bohr orbit of H atom is -13.6 eV. the possible value(s) of the excited state(s) for electrons in Bohr orbits of hydrogen is (are) .. [ IIT 1998]
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a) -3.4 eV
0%
b) - -4.2 eV
0%
c)-6.8 eV
0%
d)+6.8 eV
Explanation
Values of energy in excited state=(-13.6/n2) eVAnswer: (a)
Q.33
the configuration 1s2, 2s2 2p5 3s1 shows .....[AIIMS 1997]
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a) ground state of fluorine
0%
b) excited state of fluorine
0%
c)excited state of Neon atom
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d)excited sate of O2-
Explanation
Total number of electrons are 10 for ground state of Ne outer orbit configuration is 2s2 2p6 Answer:(c)
Q.34
Azimuthal quantum number determines the .... [ BHU 1995]
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a) size
0%
b) spin
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c) orientation
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d) angular momentum of orbitals
Explanation
Angular momentum = Answer: (d)
Q.35
Which is not true with respect to cathode rays? [ kerala CEE 2001]
0%
a)A stream of electron
0%
b) Charged particles
0%
c)Move with speed same as that of light
0%
d)can be deflected by magnetic fields
Explanation
Answer: (c)
Q.36
In H atom electron jumps from 3rd to 2nd energy level, the energy released is ... [ AFMC 1997]
0%
a) 3.03 ×10-19 J/atom
0%
b) 1.03 ×10-19 J/atom
0%
c)3.03 ×10-12 J/atom
0%
d)6.06 ×10-19 J/atom
Explanation
Answer: (a)
Q.37
if the planck's constant h=6.6×10-34 Js, the de Broglie wave length of a particle having momentum of 3.3×10-24 kg m s-1 will be ... [ Pb CET 1998]
0%
a) 0.002 Ao
0%
b)0.5 Ao
0%
c)2.0 Ao
0%
d)500 Ao
Explanation
Answer:(c)
Q.38
Two particles A and B are in motion. if the wavelength associated with the particle A is 5.0 ×10-8 m, the wavelength of particle B having momentum half of A is
0%
a) 2.5×10-8 m
0%
b) 1.25×10-8 m
0%
c) 1.0×10-7 m
0%
d) 1.0×10-8 m
Explanation
λ ∝ (1/p) Answer: (c)
Q.39
For which of the following species, Bohr's theory is not applicable? [ DEC 2000]
0%
a)Be3+
0%
b) Li2+
0%
c)He2+
0%
d)H
Explanation
HE2+ don't have any electronAnswer: (c)
Q.40
Chloride ion and potassium ion are isoelectronic then [ KCET 2002]
0%
a) their size are same
0%
b) Chloride ion is bigger than potassium ion
0%
c)potassium ion is relatively bigger
0%
d)depends upon the other cation or anion
Explanation
C- ion has 17 protons in the nucleus while K+ has 19 protons. Thus nuclear charge of K+ is greater and hence its size is smallerAnswer: (b)
Q.41
The wave number of first line of Balmaer series of hydrogen is 15200 cm-. The wave number of first Balmaer line of Li2+ ion is ..[ IIT 1992]
0%
a)15200 cm-1
0%
b) 60800 cm-1
0%
c)76000 cm-1
0%
d)136800 cm-1
Explanation
Wave number Answer:(d)
Q.42
In the Bohr's orbit, what is the ratio of total kinetic energy and total energy of the electrons ... [ Rajasthan PMT 2002]
0%
a) -1
0%
b) -2
0%
c) +1
0%
d) +2
Explanation
But electrostatic force=centrifugal force Answer: (a)
Q.43
Identify the least stable among the following ... [ IIT 2002]
0%
a)Li-
0%
b) Be-
0%
c)B-
0%
d)C-
Explanation
E.C. of Li-=1s2, 2s2 Be-=1s2 2s2 2p1B-=1s2 2s2 2px1, 2py1C-=1s2 2s2 2px1, 2py12pz1Evidently the least stable is Be-sr/>Answer: (b)
Q.44
In a Bohr's atomic model, when an electron jumps from n=3 to n=1 how much energy will be emitted? [ CBSE PMT 1996]
0%
a) 2.15 ×10-11 ergs
0%
b) 2.389 ×10-12 ergs
0%
c)0.239 ×10-10 erg
0%
d)0.1936 ×10-10 erg
Explanation
Answer: (d)
Q.45
The work function of a metal is 4.2eV. If radiations of 2000Ao fall on the metal then the kinetic energy of the fastest photo electron is
0%
a) 1.6 ×10-19 J
0%
b) 16 ×1010 J
0%
c)3.2 ×10-19 J
0%
d)6.4 × 10-10 J
Explanation
Work function φ=4.2 eV=4.2 × 1.60 ×10-19 J φ=6.72 ×10-19 JEnergy of radiation ∴ K.E. of electron==(9.94 - 6.72) ×10-19 J K.E of electron=3.32 ×10-19 J Answer:(c)
Q.46
An electron moving with velocity 'v' is found to have a certain value of de-broglie wave length. the velocity to be possessed by the neutron to have the same de-Broglie wave length is ...
0%
a) 1840/v
0%
b) 1840v
0%
c) v/1840
0%
d) v
Explanation
mass of neutron=1840× mass of electron for equal wavelengths momentum of neutron=momentum of electron ∴ vn × 1840(m)=v×mvn=v/1840 Answer: (c)
Q.47
Which of the following atom has no neutron in its nucleus? [ CPMT 2000]
0%
a)Helium
0%
b) Lithium
0%
c)Protium
0%
d)Tritium
Explanation
Answer: (c)
Q.48
The frequency of yellow light having wavelength 600nm is ... [MPPMT 2002]
0%
a) 5.0 ×1014Hz
0%
b) 2.5 ×107 Hz
0%
c)5 ×107 Hz
0%
d)2.5 × 1014 Hz
Explanation
ν c/λAnswer: (a)
Q.49
The energy of the first electron in helium will be ...[ Bihar CEE 2002]
0%
a) -13.6 eV
0%
b) -54.4 eV
0%
c)-5.44 eV
0%
d)zero
Explanation
Answer:(b)
Q.50
The wavelength associated with golf ball weighing 200g and moving at speed of 5m/h is of the order... [ IIT 2001]
0%
a) 10-10 m
0%
b) 10-20 m
0%
c) 10-30 m
0%
d) 10-40 m
Explanation
velocity 5 m/h=5/3600=1.4 ×103 weight=200gm=200×10-3 kg Answer: (c)
0 h : 0 m : 1 s
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