KEAM SERIES Chemistry
Structure Of Atom
19 previous year questions.
Volume: 19 Ques
Yield: Medium
High-Yield Trend
8
2026 6
2025 2
2023 2
2022 1
2019 Chapter Questions 19 MCQs
01
PYQ 2019
medium
chemistry ID: keam-201
Maximum number of photons emitted by a bulb capable of producing monochromatic light of wavelength is ..........., if and is supplied for one hour.
1
2
3
4
02
PYQ 2022
medium
chemistry ID: keam-202
A particle of mass 6.6\times 10-31kg is moving with a velocity of 1\times 107ms-1. The de Broglie wavelength (in A) associated with the particle, is (h=6.6\times 10-34 Js)
1
1
2
10
3
5
4
2
5
4
03
PYQ 2022
hard
chemistry ID: keam-202
A di-negative ion of the element X consists of 10 electrons and 8 neutrons. A dipositive ion of the element Y consists of 12 protons. The number of neutrons in Y is 1.5 times the number of electrons in atom X. Then the mass numbers of X and Y would be in the ratio
1
1:2
2
2:3
3
3:2
4
2:5
5
1:3
04
PYQ 2023
medium
chemistry ID: keam-202
Which of the following statements is WRONG?
1
The bond order of He2is zero;so He2,molecule is unstable.
2
Li2 molecule is diamagnetic.
3
O2 molecule contains two unpaired electron and is paramagnetic.
4
C2 molecule is paramagnetic in vapour phase.
5
H2 molecule has no unpaired electrons.
05
PYQ 2023
medium
chemistry ID: keam-202
Which of the following statement cannot be explained by the proposals of Dalton's atomic theory?
1
Reorganisation of atoms in chemical reactions
2
ldentical properties of all atoms of given element
3
The reason for combining of atoms
4
Formation of compounds from the combination of elements in a fixed ratio
5
Matter consists of individual atoms
06
PYQ 2025
medium
chemistry ID: keam-202
Which of the following is correct about the stability of half-filled and completely filled subshells?
(i) Relatively small shielding
(ii) Larger coulombic repulsion energy
(iii) Smaller exchange energy
(iv) Smaller coulombic repulsion energy
(v) Larger exchange energy
(i) Relatively small shielding
(ii) Larger coulombic repulsion energy
(iii) Smaller exchange energy
(iv) Smaller coulombic repulsion energy
(v) Larger exchange energy
1
(i), (ii) and (iii)
2
(i), (iii) and (v)
3
(i), (iv) and (v)
4
(ii), (iii) and (v)
5
(i), (ii) and (iv)
07
PYQ 2025
medium
chemistry ID: keam-202
Which of the following have a complete octet?
1
BeCl
2
BF
3
SnCl
4
LiCl
08
PYQ 2025
medium
chemistry ID: keam-202
Which of the following is diamagnetic?
1
[MnCl ]
2
[Fe(CN) ]
3
[Co(C O ) ]
4
[FeF ]
09
PYQ 2025
medium
chemistry ID: keam-202
Properties of canal rays:
1
They are positively charged.
2
They are negatively charged.
3
They travel in straight lines.
4
They have no mass.
10
PYQ 2025
medium
chemistry ID: keam-202
The carboxylic acid used widely in the leather industry is?
1
Acetic acid
2
Formic acid
3
Butyric acid
4
Propionic acid
11
PYQ 2025
medium
chemistry ID: keam-202
IUPAC name of C H is:
1
Hexane
2
Cyclohexane
3
Heptane
4
Octane
12
PYQ 2026
medium
chemistry ID: keam-202
Which of the following set of compounds does not follow octet rule?}
1
and
2
and
3
and
4
and
5
and
13
PYQ 2026
medium
chemistry ID: keam-202
Which of the following statement is NOT the postulate of VSEPR theory?}
1
Where two or more resonance structures can represent a molecule, the VSEPR model is not applicable to any such structure.
2
A multiple bond is treated as if it is a single electron pair and the two or three electron pairs of a multiple bond are treated as a single super pair.
3
The shape of a molecule depends upon the number of valence shell electron pairs around the central atom.
4
Pairs of electrons in the valence shell repel one another since their electron clouds are negatively charged.
5
The valence shell is taken as a sphere with the electron pairs localising on the spherical surface at maximum distance from one another.
14
PYQ 2026
medium
chemistry ID: keam-202
The number and type of bonds between nitrogen and three oxygen atoms in by Lewis representation is}
1
one pi ( ) and 3 sigma ( ) bonds
2
one pi ( ) and 2 sigma ( ) bonds
3
two pi ( ) and 3 sigma ( ) bonds
4
one pi ( ) and 4 sigma ( ) bonds
5
two pi ( ) and 2 sigma ( ) bonds
15
PYQ 2026
medium
chemistry ID: keam-202
The correct increasing order of the ionic radii of the isoelectronic species and is}
1
2
3
4
5
16
PYQ 2026
medium
chemistry ID: keam-202
The set of elements which has exceptional electronic configurations not obeying Aufbau principle is}
1
K, Ca, Cr \& Cu
2
Ca, Cr, Nb \& Cu
3
Ca, Cr, Ag \& Cu
4
Cr, Cu, Ag \& Ru
5
Na, Rh, Cr \& Cu
17
PYQ 2026
medium
chemistry ID: keam-202
Which of the following ions are isoelectronic?
1
2
3
4
5
18
PYQ 2026
medium
chemistry ID: keam-202
The correct increasing order of number of electrons around the central atom in the following molecules is
1
2
3
4
5
19
PYQ 2026
medium
chemistry ID: keam-202
An odd electron molecule among the following is (2015)
1
CO
2
SO
3
CO
4
NO
5
O