Class 11 Chemistry MCQ Chapter 2 Structure of Atom
Preparing for your Chemistry exam? Our Class 11 Chemistry MCQ Chapter 2 Structure of Atom English Medium resource is designed to help AHSEC Higher Secondary First Year students practice important objective questions and strengthen their understanding of atomic structure.
The chapter Structure of Atom explains the fundamental building blocks of matter. Students will learn about subatomic particles, atomic models, electromagnetic radiation, Bohr’s theory, quantum numbers, atomic orbitals, and the electronic configuration of atoms. These topics are essential for understanding the behavior of atoms and form the basis of many advanced Chemistry concepts.
The MCQs provided here are prepared according to the latest AHSEC syllabus and examination pattern. By solving these questions, students can revise key concepts, improve their problem-solving abilities, and become more confident in answering exam-oriented questions.
Whether you are preparing for school tests, annual examinations, or the AHSEC HS First Year Examination, these MCQ solutions will help you revise the chapter effectively and achieve better results in Chemistry.
Part: I
Class 11 Chemistry MCQ Chapter 2 Structure of Atom
Selected VSA & MCQ
I. Very Short Answer Questions (VSA)
Q What is an atom?
Ans: The smallest unit of an element that retains its chemical properties.
Q Who discovered the electron?
Ans: J. J. Thomson.
Q Who discovered the proton?
Ans: Eugen Goldstein.
Q Who discovered the neutron?
Ans: James Chadwick.
Q What is atomic number?
Ans: Number of protons in the nucleus.
Q What is mass number?
Ans: Sum of protons and neutrons.
Q Define isotope.
Ans: Atoms of same element with different mass numbers.
Q Define isobar.
Ans: Atoms with same mass number but different atomic numbers.
Q What is orbital?
Ans: Region of space where probability of finding electron is maximum.
Q What is quantum number?
Ans: Numbers that describe position and energy of electrons.
Q What is principal quantum number?
Ans: It denotes main energy level (n).
Q What is azimuthal quantum number?
Ans: It defines shape of orbital (l).
Q What is magnetic quantum number?
Ans: It defines orientation of orbital (m).
Q What is spin quantum number?
Ans: It describes spin of electron (+½ or −½).
Q What is Aufbau principle?
Ans: Electrons fill orbitals in order of increasing energy.
Q What is Pauli exclusion principle?
Ans: No two electrons have same set of quantum numbers.
Q What is Hund’s rule?
Ans: Electrons occupy degenerate orbitals singly first.
Q What is de Broglie equation?
Ans: Relation between wavelength and momentum of particle.
Q What is Heisenberg uncertainty principle?
Ans: Impossible to determine exact position and momentum simultaneously.
Q What is electromagnetic radiation?
Ans: Energy transmitted through space as waves.
Q What is wavelength?
Ans: Distance between two successive crests.
Q What is frequency?
Ans: Number of waves per second.
Q What is photoelectric effect?
Ans: Emission of electrons on exposure to light.
Q What is Bohr model?
Ans: Electrons revolve in fixed energy levels.
Q What is ground state?
Ans: Lowest energy state of atom.
Q What is excited state?
Ans: Higher energy state after absorbing energy.
Q What is ionisation energy?
Ans: Energy required to remove electron.
Q What is electron configuration?
Ans: Distribution of electrons in orbitals.
II. Multiple Choice Questions (MCQs)
Q Who discovered electron?
(a) Rutherford
(b) Thomson
(c) Bohr
(d) Chadwick
Ans: (b)
Q Charge of electron is:
(a) positive
(b) negative
(c) neutral
(d) variable
Ans: (b)
Q Proton was discovered by:
(a) Thomson
(b) Goldstein
(c) Rutherford
(d) Bohr
Ans: (b)
Q Neutron was discovered by:
(a) Rutherford
(b) Thomson
(c) Chadwick
(d) Dalton
Ans: (c)
Q Atomic number represents:
(a) neutrons
(b) electrons
(c) protons
(d) nucleons
Ans: (c)
Q Mass number equals:
(a) p + e
(b) p + n
(c) e + n
(d) only p
Ans: (b)
Q Isotopes have same:
(a) mass number
(b) atomic number
(c) neutrons
(d) electrons
Ans: (b)
Q Orbital is:
(a) path of electron
(b) region of probability
(c) fixed circle
(d) shell
Ans: (b)
Q Principal quantum number is:
(a) n
(b) l
(c) m
(d) s
Ans: (a)
Q Azimuthal quantum number is:
(a) n
(b) l
(c) m
(d) s
Ans: (b)
Q Maximum electrons in orbital is:
(a) 1
(b) 2
(c) 3
(d) 4
Ans: (b)
Q Aufbau principle states:
(a) high to low energy
(b) low to high energy
(c) random filling
(d) none
Ans: (b)
Q Pauli principle states:
(a) same quantum numbers allowed
(b) not allowed
(c) partial allowed
(d) random
Ans: (b)
Q Hund’s rule states:
(a) pairing first
(b) single occupancy first
(c) no filling
(d) random
Ans: (b)
Q de Broglie equation relates:
(a) energy and mass
(b) wavelength and momentum
(c) velocity and mass
(d) charge and energy
Ans: (b)
Q Uncertainty principle given by:
(a) Bohr
(b) Heisenberg
(c) Planck
(d) Einstein
Ans: (b)
Q Planck constant unit is:
(a) J
(b) Js
(c) m
(d) s
Ans: (b)
Q Frequency unit is:
(a) m
(b) Hz
(c) J
(d) kg
Ans: (b)
Q Wavelength unit is:
(a) m
(b) s
(c) kg
(d) J
Ans: (a)
Q Photoelectric effect shows:
(a) wave nature
(b) particle nature
(c) both
(d) none
Ans: (b)
Q Bohr model applies to:
(a) multi-electron atoms
(b) hydrogen atom
(c) molecules
(d) solids
Ans: (b)
Q Ground state means:
(a) highest energy
(b) lowest energy
(c) medium energy
(d) none
Ans: (b)
Q Excited state means:
(a) lower energy
(b) higher energy
(c) same energy
(d) none
Ans: (b)
Q Ionisation energy is:
(a) remove proton
(b) remove electron
(c) add neutron
(d) none
Ans: (b)
Q Electron configuration follows:
(a) Aufbau
(b) Pauli
(c) Hund
(d) all
Ans: (d)
Q Maximum electrons in shell =
(a) n
(b) 2n
(c) 2n²
(d) n²
Ans: (c)
Q Magnetic quantum number is:
(a) n
(b) l
(c) m
(d) s
Ans: (c)
Q Spin quantum number is:
(a) ±1
(b) ±½
(c) 0
(d) 1
Ans: (b)
Q Energy of a photon depends on:
(a) wavelength
(b) frequency
(c) both
(d) none
Ans: (c)
Q Assertion: An electron has a wave nature.
Reason: De Broglie proposed the wave nature of matter.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
Q Assertion: Position and momentum cannot be known exactly.
Reason: Heisenberg uncertainty principle.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
Q Assertion: Orbitals have definite shapes.
Reason: Defined by the azimuthal quantum number.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
Q Assertion: The Pauli principle restricts electrons.
Reason: No two electrons have the same quantum numbers.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
Q Assertion: Hund’s rule increases stability.
Reason: Electrons occupy singly first.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
Q Assertion: The Bohr model explains the hydrogen spectrum.
Reason: Electrons move in fixed orbits.
(a) A Both A and R are true, but R is not the correct explanation of A
(b) Both A and R are true, and R is the correct explanation of
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (b)
Q Assertion: The photoelectric effect supports the particle nature.
Reason: Electrons are emitted instantly.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a)
