NCERT Solutions for class 11 Chemistry | Chapter : Structure of Atom

Questions
1 How many orbitals can have the following set of quantum numbers, n = 3, l = 1, m1 = 0 ?
A 3
B 1
C 4
D 2

Answer:1
2 Electronic configuration of the outer shell of the element Gd with atomic number 64 is
A 4f4 5d5 6s1
B 4f3 5d5 6s2
C 4f5 5d4 6s1
D 4f7 5d1 6s2

Answer:4f7 5d1 6s2
3 Maximum number of electrons in a subshell can be
A 4l + 2
B 4l – 2
C 2n2
D 2l + 1

Answer:4l + 2
4 The orientation of atomic orbitals depends on their
A spin quantum number
B magnetic quantum number
C azimuthal quantum number
D principal quantum number

Answer:magnetic quantum number
5 A gas X has Cp and Cv ratio as 1.4, at NTP 11.2 L of gas X will contain_______ number of atoms
A 1.2 × 1023
B 3.01 × 1023
C 2.01 × 1023
D 6.02 × 1023

Answer:6.02 × 1023
6 Number of unpaired electrons in N2+
A 3
B 1
C 2
D 0

Answer:1
7 The excitation energy of a hydrogen atom from its ground state to its third excited state is
A 12.75 eV
B 0.85 eV
C 10.2 eV
D 12.1 eV

Answer: 12.75 eV
8 3p orbital has _____ radial nodes
A three
B two
C one
D none

Answer: one
9 A 0.66 kg ball is moving with a speed of 100 m/s. Find its wavelength
A 6.6 × 10-34 m
B 6.6 × 10-32 m
C 1.0 × 10-32 m
D 1.0 × 10-35 m

Answer:1.0 × 10-35 m
10 If an atom has four unpaired electrons. What is likely to be the total spin of the electron?
A 1
B 2.5
C 2
D 4

Answer: 2
11 The electronic configuration for oxygen is written as 1s2 2s2 2p4. Which rule will this configuration be violating?
A Aufbau’s principle.
B Hund’s rule.
C Pauli’s exclusion principle.
D None of the above.

Answer:None of the above.
12 What is the sequence to label the subshells in an atom?
A S, p, d, f, g
B S, p, p, f, d
C S, s, p, p, d, f, g
D S, p, g, d, f

Answer:S, p, d, f, g
13 The isotopes of a neutral atom of an element differ in which of these?
A Physical properties.
B Chemical properties.
C Atomic number.
D Mass number.

Answer:Atomic number.
14 The maximum mass of an atom is concentrated in which of these?
A Nucleus.
B Neutrons.
C Protons.
D Electrons.

Answer:Nucleus.
15 An atom differs from an ion with respect to which of the following?
A Number of protons.
B Nuclear charge.
C Number of electrons.
D Mass number.

Answer: Number of electrons.
16 The electronic configuration of atomic number 20 of an atom is which of the following?
A 2, 6, 6, 2
B 2, 8, 8, 2
C 2, 4, 6, 2
D 2, 4, 6, 2

Answer: 2, 8, 8, 2
17 Who proposed the atomic theory?
A John Dalton.
B Robert Millikan.
C J. J. Thomson.
D Neils Bohr.

Answer:Robert Millikan.
18 What happens to the atomic number during a chemical reaction?
A It increases.
B It changes.
C Remains the same.
D Changes alternatively.

Answer: Remains the same.
19 Atoms that have the same mass number and different atomic number are called?
A Isotopes.
B Isotones.
C Isobars.
D Isomers.

Answer:Isotopes
20 Which of the following determines the chemical properties?
A Number of protons.
B Number of electrons.
C Number of neutrons.
D None of these.

Answer:Number of electrons.

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