82 Structure of atom
Composition of Atom (Electron, Proton and Neutron)
Ba sic L Level 1.
2.
The fundamental particles present in the nucleus of an atom are (a) Alpha particles and electrons
(b) Neutrons and protons
(c) Neutrons and electrons
(d) Electrons, neutrons and protons
Cathode rays were discovered by (a) William Crookes
3.
6.
(b) Electrons
(c) Neutrons
(d) -particles -particles [CPMT 1982]
(b) Charge only
(c) No mass and charge
(d) Mass and charge both
Cathode rays are made up of
[AMU 1983]
(a) Positively charged particles
(b) Negatively charged particles
(c) Neutral particles
(d) None of these
Cathode rays are produced when the pressure in the discharge tube is of the order of (b) 10 6 cm of Hg Hg
(c) 1 cm of Hg Hg
(d) 10 2 to 10 3 mm of Hg Hg
(b) A ratio receiver
(c) A television set
(d) A Van de Graff generator
Cathode-ray tube is used in (a) Compound microscope
8.
(d) None of these
Cathode rays have
(a) 76 cm of Hg Hg 7.
(c) Rutherford
[JIPMER 1991; NCERT 1976]
(a) Mass only 5.
(b) J. Stoney
Cathode rays are (a) Protons
4.
[CPMT 1983, 84]
Which of the following statement is not correct regarding cathode rays (a) Cathode rays rays originate originate from from the the cathode (b) Charge and mass of the particles particles constituting cathode rays depends upon the the nature of the gas (c) Charge and mass of the particles particles present does not not depend upon the material of the cathode (d) The ratio charge/mass of the particles particles is much greater than that that of anode rays rays
9.
10.
Which one is not true for the cathode rays (a) They have kinetic energy
(b) They cause certain substances to show fluorescence
(c) They travel in straight line
(d) They are electromagnetic waves
The electron is
[Delhi PMT 1982; MADT Bihar 1980]
(a) -rays -rays particle 11.
10
4.8 10
esu
28 9.1 10 g
19
(b)
1.6 10
(b)
9.1 1025 g
C
(c) Unit negative
(d) All
(c)
10 9.1 10 g
(d)
18 9.1 10 g
Which of the following has the same mass as that of an electron (a) Photon
14.
(d) Positron
Mass of an electron is (a)
13.
(c) Hydrogen ion
The charge on an electron is (a)
12.
(b) -ray -ray particle
(b) Neutron
[AFMC 2002]
(c) Positron
(d) Proton
Density of the electron is (a)
17 2.17 10 g / / mL
(b)
17 4.38 10 g / / mL
(c)
14 2.17 10 g / / mL
(d) None of these
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Structure of atom 83 15.
16.
17.
A strong argument for the particle nature of of cathode rays is that they they (a) Produce fluorescence
(b) Travel through vacuum
(c) Get deflected by electric and magnetic fields
(d) Cast shadow
In the discharge tube emission emission of cathode rays requires requires (a) Low potential and low pressure
(b) Low potential and high pressure
(c) High potential and high pressure
(d) High potential and low pressure
The minimum real charge on any particle which can exist is (a) 1.6 1019 Coulomb
18.
[CPMT 1986; MLNR 1986]
(b) 1.6 1010 Coulomb
[Rajasthan PMT 2000]
(c)
4.8 1010 Coulomb
(d) Zero
Which of the following statement is incorrect
[CPMT 1973 ; BHU 1985]
(a) The charge on an electron and on a proton are equal and opposite (b) Neutrons has no charge (c) Electrons and protons have the same weight weight (d) The mass of a proton and a neutron are nearly nearly identical 19.
Ratio of masses of proton and electron is (a) Infinite
20.
22.
6.023 1023 g
25.
9.1 1028 kg
(d) 2 gm 2 gm [NCERT 1977]
(d) Of different values of charge and mass ratio
Anode rays were discovered discovered by
[DPMT 1985]
(b) J. Stoney
(c) Rutherford
(d) J.J. Thomson
The nature of anode rays depends on
[CPMT 1987]
(b) Nature of discharging tube
(c) Nature of residual gas
(d) All of these
Proton is
[NCERT 1976 ; CPMT 1971]
(a) An ionized hydrogen molecule
(b) An -ray -ray particle
(c) A fundamental particle
(d) Nucleus of heavy hydrogen
Penetration power of proton is
[BHU 1985 ; CPMT 1982, 88]
(b) Less than electron
The ratio of specific charge of a proton and an
(c) More than neutron
(d)
None of these
-particle is
[MP PET 1999]
(b) 1 : 2
(c) 1 : 4
(d) 1 : 1
(c) Same
(d) None of these
The e /m /m for positive rays in comparison to cathode rays is (a) Very low
28.
(c)
(c) Bearing positive and negative charges respectively
(a) 2 : 1 27.
(b) 1.008 g and 0.55 mg
(b) Bearing different magnitude of charge
(a) More than electron 26.
(d) None of these
(a) Of different masses
(a) Nature of electrode 24.
(c) 1.8
A mass spectrograph is an instrument instrument which is capable of differentiating differentiating and identifying particles particles
(a) Goldstein 23.
1.8 103
The mass of a mole of proton and electron is (a)
21.
(b)
[BHU 1998]
(b) High
What is false to say about anode rays (a) Their e /m /m ratio depends upon the nature of residual gas (b) They are deflected by electrical and magnetic field (c) Their e /m /m ratio is constant (d) These are produced by ionization of molecules of the residual residual gas
29.
Nuclei tend to have more neutrons than protons at high mass numbers because
[Roorkee Qualifying 1998]
(a) Neutrons are neutral particles
(b) Neutrons have more mass than protons
(c) More neutrons minimize the coulomb repulsion
(d) Neutrons decrease the binding energy
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84 Structure of atom 32.
Who discovered neutron
[IIT 1982 ; BITS 1988 ; CPMT 1977 ; NCERT 1974 ; MP PMT 1992 ; MP PET 2002]
(a) James Chadwick 33.
14 1 14 1 6 C 1 p 7 N 0n
(b)
38.
39.
9 4 12 1 4 Be 2 He 6 C 0
(b) Neutron
n
(c) Proton
(d)
8 4 11 1 4 Be 2 He 6 C 0n
(d) Electron [NCERT 1980]
(b) 10 6 kg / cc
(c)
10 9 kg / cc
The mass of neutron is nearly
(d) 10 12 kg / cc [MLNR 1988 ; UPSEAT 1999, 2000, 02]
(b) 10 24 kg
(c)
10 26 kg
(d) 10 27 kg
Neutron is a fundamental particle carrying
[CPMT 1990]
(a) A charge of +1 unit and a mass of 1 unit
(b) No charge and a mass of 1 unit
(c) No charge and no mass
(d) A charge of –1 and a mass of 1 unit
The discovery of neutron becomes very late b ecause
[CPMT 1987 ; AIIMS 1998]
(a) Neutrons are present in nucleus
(b) Neutrons are highly unstable particles
(c) Neutrons are chargeless
(d) Neutrons do not move
Which one of the following pairs is not correctly matched (a) Rutherford-Proton
40.
(c)
The density of neutrons is of the order
(a) 10 23 kg 37.
11 2 12 1 5 B 1 D 6 C 0n
[Delhi PMT 1983 ; MP PET 1999]
(a) 10 3 kg / cc 36.
(d) Rutherford
Heaviest particle is (a) Meson
35.
(c) J. J. Thomson
Which of the following reactions led to the discovery of the neutron (a)
34.
(b) William Crooks
(b) J. J. Thomson-Electron
[MP PET 2002]
(c) J. H. Chadwick-Neutron
(d) Bohr-Isotope
An elementary fundamental fundamental particle is
[CPMT 1973]
(a) An element present in a compound
(b) An atom present in an element
(c) A sub-atomic particle
(d) A fragment of an atom
Advance Le L Level
41.
The charge of an electron is
1.6 10
19
C . The value of free charge on Li ion will be [AFMC 2002 ; Karnataka CET (Engg.) 2002]
(a) 42.
(b) 1 1019 C
(c)
1.6 1019 C
(d)
2.6 1019 C
The charge on an electron is 4.8 1010 esu . What is the value of charge in Li ion (a)
43.
3.6 1019 C
4.8 1010 esu
(b)
9.6 1010 esu
(c)
1.44 10 9 esu
[CPMT 1997]
(d)
2.4 1010 esu
The specific charge for positive rays is much less than the specific charge for cathode rays. This is because
[CPMT 1990]
(a) Positive rays are positively positively charged (b) Charge on positive positive rays is less (c) Positive rays comprise ionised ionised atoms whose mass is much higher higher (d) Experimental method method for determination is wrong 44.
The increasing order (lowest first) for the values of e /m /m (charge/mass) for (a) e, p, p, n,
(b) n, p, p, e,
(c) n, p, p, , e
[IIT 1984]
(d) n, , p, e
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Structure of atom 85 Atomic number, Mass Mass number and Atomic species
Basic Le L Level 47.
Nitrogen atom has an atomic number of 7 and oxygen has an atomic number 8. The total number of electrons in a nitrate ion will be [Pb. PMT 2000]
(a) 8 48.
53.
56.
(b) 1
[MP PMT 1986]
(c) 2
(d) 3 [CPMT 1972; Delhi PMT 1982]
(b) Protons
[CPMT 1976]
(c) Neutrons
(b) 30
(d) Does not differ
(c) 36
The atomic number of an element represents
[CPMT 1983; CBSE 1990; NCERT 1973; AMU 1984]
(b) Number of protons in the nucleus
(c) Atomic weight of element
(d) Valency of element
The mass of an atom is constituted mainly by (b) Neutron and electron
[Delhi PMT 1984. 91; AFMC 1990]
(c) Neutron and proton
(d) Proton and electron
Which of the following is always a whole number (b) Atomic radii
[CPMT 1980]
(d) 56
(a) Number of neutrons in the nucleus
[CPMT 1976, 81, 86]
(c) Equivalent weight
(d) Atomic number
The electronic configuration of a dipositive metal M 2 is 2, 8, 14 and its atomic weight is 56 a.m.u. The number of neutrons in its nuclei would be [MNR 1984, 89; Kerala PMT 1999] (b) 32
(c) 34
(d) 42
The total number of unpaired electrons in d -orbitals of atoms of element of atomic number 29 is (b) 1
(c) 0
Chlorine atom differs from chloride ion in the number of (b) Neutron
(b) 44
[CPMT 1983]
(d) 5 [NCERT 1972; MP PMT 1995]
(c) Electrons
The number of electrons in one molecule of CO2 are (a) 22
62.
(d) 92
An atom has 26 electrons electrons and its atomic weight is 56. 56. The number of neutrons neutrons in the nucleus of of the atom will be
(a) Proton 61.
(c) 69
Sodium atom differs from sodium ion in the number of
(a) 10 60.
(b) 46
(d) Four protons and two electrons
(a) 30 59.
(d) 0
(c) Two neutrons and two protons
(a) Atomic weight 58.
(c) 3
(b) Four neutrons
(a) Neutron and neutrino 57.
(b) 2
[CPMT 2003]
(a) Four protons
(a) 26 55.
(d) 35
The nucleus of helium contains
(a) Electron 54.
(c) 18
Number of neutrons in heavy hydrogen atom is (a) 0
52.
(b) 20
[MP PMT 2003]
The total number of protons in one molecule of nitrogen dioxide (a) 23
51.
(d) 64
The number of neutron in tritium is (a) 1
50.
(c) 32
The number of electrons in Cl ion is (a) 19
49.
(b) 16
(d) Protons and electrons [IIT 1979; MP PMT 1994; Rajasthan PMT 1999]
(c) 66
The nitrogen atom has 7 protons and 7 electrons, the nitride ion ( N 3 ) will have
(d) 88 [NCERT 1977]
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86 Structure of atom 64.
If W If W is is atomic weight and N and N is is the atomic number of an element, then (a) Number of e 1
W N
(c) Number of 1 H 1 65.
W N
(b) Number of 0 n1
W N
(d) Number of 0 n1
N
The number of electrons in the atom which has 20 protons in the nucleus is (a) 20
66.
[CPMT 1971, 80, 89]
(b) 10
(c) 30
Six protons are found in the nucleus of (a) Boron
[CPMT 1981, 93; CBSE 1989]
(d) 40 [CPMT 1977, 80, 81; NCERT 1975, 78]
(b) Lithium
(c) Carbon
(d) Helium (d) Al
67.
A sodium cation has different different number of electrons electrons from (c) Li Li
68.
(b) F An atom which has lost one electron electron would be (a) Negatively charged
(b) Positively charged
(c) Electrically neutral
(d) Carry double positive charge
(a)
69.
70.
71.
72.
O2
The nucleus of the element having atomic number 25 and atomic weight 55 will contain (a) 25 protons and 30 neutrons
(b) 25 neutrons and 30 protons
(c) 55 protons
(d) 55 neutrons
Positive ions are formed from the neutral atom by the (a) Increase of nuclear charge
(b) Gain of protons
(c) Loss of electrons
(d) Loss of protons
The nucleus of the atom consists of
(d) Proton, neutron and electron
The number of electrons in an atom of an element is equal to its (b) Atomic number
[BHU 1979]
(c) Equivalent weight
(d) Electron affinity
Neutrons are found in atoms of all elements except in (b) Oxygen
[MP PMT 1997]
(c) Argon
(d) Hydrogen
A transition metal X metal X has has a configuration [ Ar ] 3d 4 in its + 3 oxidation state. Its atomic number is Number of electrons in
(b) 26 CONH 2
(a) 22 76.
[CPMT 1973; 74, 78, 83, 84; MADT Bihar 1980; Delhi PMT 1982, 85, MP PMT 1999]
(c) Neutron and electron
(a) 25 75.
[CPMT 1976]
(b) Proton and electron
(a) Chlorine 74.
[CPMT 1986; MP PMT 1987 ]
(a) Proton and neutron
(a) Atomic weight 73.
[CPMT 1986]
(c) 22
[EAMCET 1990]
(d) 19
is
[AMU 1988]
(b) 23
(c) 20
(d) 28
following statements is not correct about Ca atom Ca has atomic number 20 and atomic weight 40. Which of the following
[MP PET 1993]
(a) The number of electrons is is same as the number number of neutrons (b) The number of nucleons is double double of the number number of electrons electrons (c) The number number of protons is half half of the number number of neutrons neutrons (d) None of these 77.
Which of the following atom has more electrons than than neutrons (b) F
(a) C 78.
80.
O2
The present atomic weight scale is based on (a)
79.
(c)
C12
The nucleus of the element
(b) 21 E
45
O16
(d) Al 3 [EAMCET 1988; MP PMT 2002]
(c) H 1
(d)
C13
contains
(a) 45 protons and 21 neutrons
(b) 21 protons and 24 neutrons
(c) 21 protons and 45 neutrons
(d) 24 protons and 21 neutrons
The number of electrons in the nucleus of C12 is (a) 6 (b) 12
[AFMC 1995]
(c) 0
(d) 3
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Structure of atom 87 83.
If the atomic weight of an element is 23 times that of the lightest element and it has 11 protons, then it contains [EAMCET 1986; AFMC 1989]
(a) 11 protons, 23 neutrons, 11 electrons (c) 11 protons, 12 neutrons, 11 electrons 84.
The nucleus of tritium contains (a) 1 proton + 1 neutron
85.
(b) 11 protons, 11 neutrons, 11 electrons (d) 11 protons, 11 neutrons, 23 electrons [MP PMT 2002]
(b) 1 proton + 3 neutron
(c) 1 proton + 0 neutron
(d) 1 proton + 2 neutron
The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is [CPMT 1997; Pb. PMT 1999; MP PMT 1999 ]
(a) 17 86.
(b) 37
(d) 38
40 The number of electrons in [19 K ]1 is
(a) 19 87.
(c) 2
[CPMT 1997; AFMC 1999]
(b) 20 40
In the nucleus of 20 Ca
(c) 18
(d) 40
there are
[CPMT 1990; EAMCET 1991]
(a) 40 protons and 20 electrons
(b) 20 protons and 40 electrons
(c) 20 protons and 20 neutrons
(d) 20 protons and 40 neutrons
88.
The atomic weight of an element is 39. The number of neutrons in its nucleus is one more than the number of protons. The number of protons, neutrons and electrons respectively in its atom would be [MP PMT 1997] (a) 19, 20, 19 (b) 19, 19, 20 (c) 20, 19, 19 (d) 20, 19, 20
89.
CO has same electrons as or the ion that is iso-electronic with CO is (a) N 2
90.
(b) Mg 2
(c)
(b) N 2O
(c) NO
[CBSE 1994]
(b) F
(c)
Tl
(b) I and IV
II
(d) Na CH 3
III
(b) He
[IIT 1993]
IV
(c) I and III
(d) II, III and IV [AFMC 1995; Bihar MEE 1997]
(c) He
(d) Be [EAMCET 1989]
(b) Na Na , Cl
(c)
Na Na, Ar
(d) Mg , Ar
(b) N 3 , F , Na Na
(c) Be, Al 3 , Cl
[AIEEE 2003]
(d)
Ca 2 , Cs , Br
Which of the following are iso-electronic and isostructual NO NO3 , CO32 , ClO3 , SO3 (a) NO NO3 , CO32
(b)
SO3 , NO3
(c)
ClO3 , CO32
[IIT Screening 2003]
(d)
CO32 .SO3
Which of the following atoms and ions are iso-electronic i.e. i.e. have the same number of electrons with the neon atom (a) F
99.
(d) N 2O2
Which one of the following grouping represents a collection of iso-electronic species (a) Na Na , Ca 2 , Mg 2
98.
[CBSE 1990]
Iso-electronic species are (a) K , Cl
97.
O2
(d) Ba2
The hydride ions ( H ) are iso-electronic with (a) Li
96.
Ca 2
NH 3 Pick out the iso-electronic structures from the following, CH 3 H 3O NH
(a) I and II
95.
(d)
[CPMT 1990]
I
94.
O2
Which one of the following is not iso-electronic with O2 (a) N 3
93.
(c)
Which of the following oxides of nitrogen is iso -electronic with CO2 (a) NO2
92.
CN
Na ion is iso-electronic with
(a) Li 91.
(b)
[CPMT 1984; IIT 1982; EAMCET 1990; CBSE 1997]
(b) Oxygen atom
(c) Mg
Which of the following is iso- electronic with carbon atom (a) Na Na
(b) Al 3
[NCERT 1978]
(d) N [MP PMT 1994; UPSEAT 2000]
(c)
O 2
(d) N
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88 Structure of atom 102. Iso-electronic species is
[Rajasthan PMT 2002]
(a) F , O2
(b) F , O
(d) F , O2
(c) F , O
103. Which pair of ions is iso- electronic
(a) F and Cl
[DCE 1999]
(b) F and O
104. Tritium is the isotope of (a) Hydrogen 105. An isostere is
(c)
(d) Na and Mg 2
Na Na and K
[CPMT 2003]
(b) Oxygen
(c) Carbon
(d) Sulphur [UPSEAT 1999]
(a) NO2 and O3
(b) NO NO2 and
PO43
(c)
CO2, N 2O, NO3
(d)
OCN ClO ClO4 and OCN
106. Which of the following pair has same electronic structure
[CPMT 1992]
(a) Ca, (b) Mg , Na Ca, Ar Which of the following are iso-electronic with one a nother 107.
(c) Ag , Sn
[NCERT 1983; EAMCET 1989]
(b) K and O
(a) Na and Ne Na and Ne
(d) Ar , Cl
(c) Ne and O
(d) Na and K
108. Be 2 is iso-electronic with
[EAMCET 1998]
(a) Mg 2
(c) Li Li
(b) Na
109. The nitride ion in lithium nitride is composed of (a) 7 protons + 10 electrons (b) 10 protons + 10 electrons 110. Number of protons, neutrons and electrons in the element
(a) 89, 231, 89 111. CO2 is isostructural with (a)
(b) 89, 89, 242
89
231
(d) H [Karnataka CET 2000]
(c) 7 protons + 7 protons
(d) 10 protons + 7 electrons
is
[AFMC 1997]
(c) 89, 142, 89
(d) 89, 71, 89 [IIT 1986; MP PMT 1986, 94, 95]
(b)
SnCl2
SO2
(c) HgC HgCl 2
(d) All the above
Advance L Level
112. In an X-ray experiment, different metals are used as the target. In each case, the frequency ( ) of the radiation produced is measured. If Z= atomic number, which which of the following plots will be a straight straight line
(a) against Z against Z 113. In Moseley's equation [
(b)
1
against Z against Z
(c)
against Z against Z
(d) against
Z
a( Z b) ], which was derived from the observations made during the bombardment of metal targets with
X-rays, (a) a is independent but b depends on the metal (b) Both a and b depend on the metal (c) Both a and b are independent of the metal and are constant (d) b is independent but a depends on the metal mass of sulphur are 256 and 32 respectively, respectively, its atomicity is [Rajasthan PET 2000] 114. If molecular mass and atomic mass