Structure of Atom Class 11 MCQ

Q: What were the key observations from Rutherford's Gold Foil Experiment?

Rutherford observed that most alpha particles passed through the gold foil without deflection, some were deflected at small angles, and a very few were deflected backward. This led to the conclusion that atoms are mostly empty space with a small, dense, positively charged nucleus.

Q: How did Bohr’s Model explain the stability of the atom?

Bohr proposed that electrons revolve around the nucleus in fixed, quantized orbits without radiating energy. Energy is absorbed or emitted only when electrons jump between orbits.

Q: What is the Heisenberg Uncertainty Principle?

The Heisenberg Uncertainty Principle states that it is impossible to simultaneously determine both the exact position and momentum of an electron with absolute precision.

Q: What is the significance of the quantum numbers in atomic structure?

Quantum numbers describe the size (n), shape (l), orientation (mₗ), and spin (mₛ) of an electron’s orbital, which helps define the electron's position and behavior in an atom.

Q: What is the photoelectric effect and who explained it?

The photoelectric effect is the ejection of electrons from a metal surface when light of sufficient frequency shines on it. Albert Einstein explained this using Planck's quantum theory, showing that light behaves as particles (photons).

Question 1

Question 1: Who first proposed the existence of atoms as indivisible particles?

A. John DaltonB. Niels BohrC. Indian and Greek philosophersD. James Clerk Maxwell

Answer

C. Indian and Greek philosophers, around 400 B.C., first proposed atoms as fundamental building blocks of matter. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 2

Question 2: What was the original meaning of the word ‘atom’?

A. IndivisibleB. VisibleC. ComplexD. Energy

Answer

A. The word ‘atom’ is derived from the Greek word ‘a-tomio,’ meaning ‘indivisible’ or ‘uncut-able.’ (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 3

Question 3: Which scientist proposed the atomic theory on a firm scientific basis in 1808?

A. RutherfordB. DaltonC. FaradayD. Bohr

Answer

B. John Dalton proposed the atomic theory on a firm scientific basis in 1808. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 4

Question 4: Dalton’s atomic theory helped explain which of the following laws?

A. Law of Conservation of MassB. Law of Multiple ProportionsC. Law of Constant CompositionD. All of the above

Answer

D. Dalton’s theory explained the Law of Conservation of Mass, the Law of Multiple Proportions, and the Law of Constant Composition. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 5

Question 5: According to Dalton’s Atomic Theory, which law states that matter cannot be created or destroyed in a chemical reaction?

A. Law of Multiple ProportionsB. Law of Constant CompositionC. Law of Conservation of MassD. Law of Electromagnetic Radiation

Answer

C. The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 6

Question 6: Which law is based on the observation that a chemical compound always contains the same elements in the same proportions by mass?

A. Law of Conservation of MassB. Law of Multiple ProportionsC. Law of Constant CompositionD. Law of Definite Proportions

Answer

C. The Law of Constant Composition is based on this observation. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 7

Question 7: The Law of Multiple Proportions states that:

A. Elements can form more than one compound in different proportions.B. Mass can neither be created nor destroyed.C. Atoms cannot be divided further.D. All atoms of a given element are identical.

Answer

A. The Law of Multiple Proportions states that elements can form more than one compound in different proportions. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 8

Question 8: Dalton’s atomic theory failed to explain the behavior of which of the following?

A. Cathode raysB. Electrically charged substancesC. The periodic tableD. Electromagnetic radiation

Answer

B. Dalton’s atomic theory could not explain the behavior of electrically charged substances like glass or ebonite when rubbed with silk or fur. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 9

Question 9: Who discovered that electricity passed through an electrolyte results in chemical reactions at the electrodes?

A. J.J. ThomsonB. Ernest RutherfordC. Michael FaradayD. Niels Bohr

Answer

C. Michael Faraday showed this phenomenon in 1830. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 10

Question 10: Cathode rays were discovered using which experimental setup?

A. Gold Foil ExperimentB. Cathode Ray Discharge TubeC. Oil Drop ExperimentD. Rutherford’s Scattering Experiment

Answer

B. The Cathode Ray Discharge Tube experiment led to the discovery of cathode rays. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 11

Question 11: Which of the following is NOT a property of cathode rays?

A. They travel in straight lines in the absence of an electric or magnetic field.B. They consist of negatively charged particles.C. They originate from the anode and move towards the cathode.D. They cause fluorescent materials to glow.

Answer

C. Cathode rays originate from the cathode and move towards the anode. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 12

Question 12: What conclusion was drawn from the cathode ray experiment regarding the structure of the atom?

A. Atoms are made up of subatomic particles.B. Atoms are indivisible.C. Atoms contain positively charged particles.D. Atoms are electrically neutral.

Answer

A. The cathode ray experiment showed that atoms are made up of subatomic particles, specifically electrons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 13

Question 13: J.J. Thomson discovered the charge to mass ratio of the electron using what type of experiment?

A. Oil Drop ExperimentB. Cathode Ray Tube ExperimentC. Alpha Particle Scattering ExperimentD. X-ray Diffraction

Answer

B. Thomson discovered the charge to mass ratio of the electron using the Cathode Ray Tube Experiment. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 14

Question 14: The charge to mass ratio of the electron is measured as:

A. 1.758820 × 10^11 C kg⁻¹B. 9.1094 × 10⁻³¹ C kg⁻¹C. 1.6726216 × 10⁻²⁷ C kg⁻¹D. 6.626 × 10⁻³⁴ J s

Answer

A. The charge to mass ratio of the electron is 1.758820 × 10^11 C kg⁻¹. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 15

Question 15: Which factor does NOT influence the deflection of electrons in Thomson’s experiment?

A. The strength of the magnetic fieldB. The strength of the electric fieldC. The mass of the electronD. The charge of the positive electrode

Answer

D. The charge of the positive electrode does not directly influence the deflection of electrons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 16

Question 16: Who determined the charge on the electron using the oil drop experiment?

A. J.J. ThomsonB. Ernest RutherfordC. R.A. MillikanD. Niels Bohr

Answer

C. R.A. Millikan determined the charge on the electron using the oil drop experiment. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 17

Question 17: The charge on the electron was measured to be:

A. 1.758820 × 10^11 CB. –1.602176 × 10⁻¹⁹ CC. 9.1094 × 10⁻³¹ CD. 6.022 × 10²³ C

Answer

B. The charge on the electron is –1.602176 × 10⁻¹⁹ C. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 18

Question 18: The mass of the electron was calculated by combining Millikan’s result with Thomson’s charge to mass ratio. What is the mass of the electron?

A. 9.1094 × 10⁻³¹ kgB. 1.6726 × 10⁻²⁷ kgC. 1.0087 uD. 1.758820 × 10^11 kg

Answer

A. The mass of the electron is 9.1094 × 10⁻³¹ kg. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 19

Question 19: Protons were first observed in experiments involving what type of rays?

A. Alpha raysB. Cathode raysC. Canal raysD. Gamma rays

Answer

C. Protons were first observed in experiments involving canal rays. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 20

Question 20: The mass of a proton compared to that of an electron is approximately:

A. 2000 times greaterB. 1000 times smallerC. 500 times smallerD. Equal

Answer

A. The mass of a proton is approximately 2000 times greater than that of an electron. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 21

Question 21: Which scientist is credited with the discovery of the neutron?

A. Ernest RutherfordB. J.J. ThomsonC. James ChadwickD. R.A. Millikan

Answer

C. James Chadwick discovered the neutron in 1932. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 22

Question 22: Neutrons were discovered by bombarding which material with alpha particles?

A. GoldB. HydrogenC. BerylliumD. Lead

Answer

C. Neutrons were discovered by bombarding a thin sheet of beryllium with alpha particles. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 23

Question 23: Which of the following correctly describes the characteristics of protons?

A. They carry a negative charge.B. They have a mass similar to that of neutrons.C. They are found outside the nucleus.D. They are neutrally charged.

Answer

B. Protons have a mass similar to that of neutrons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 24

Question 24: In what year were protons first characterized as positively charged particles?

A. 1897B. 1906C. 1919D. 1932

Answer

C. Protons were first characterized as positively charged particles in 1919. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 25

Question 25: Neutrons have which of the following properties?

A. Negative charge and small massB. Positive charge and large massC. No charge and a mass slightly greater than that of protonsD. Negative charge and a mass equal to electrons

Answer

C. Neutrons have no charge and a mass slightly greater than that of protons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 26

Question 26: Which experiment led to the discovery of positively charged particles (protons)?

A. Oil Drop ExperimentB. Gold Foil ExperimentC. Cathode Ray Tube ExperimentD. Canal Ray Experiment

Answer

D. The Canal Ray Experiment led to the discovery of positively charged particles (protons). (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 27

Question 27: In Thomson’s Plum Pudding Model, the atom is described as:

A. A positive charge sphere with electrons scattered insideB. A nucleus surrounded by electrons in specific orbitsC. A nucleus containing protons and neutronsD. Electrons revolving in elliptical orbits

Answer

A. Thomson’s Plum Pudding Model describes the atom as a sphere of positive charge with electrons scattered inside. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 28

Question 28: Which of the following is a limitation of Thomson’s Plum Pudding Model?

A. It could not explain the overall neutrality of the atom.B. It failed to explain the results of later experiments.C. It predicted the existence of neutrons incorrectly.D. It overestimated the number of protons in the nucleus.

Answer

B. Thomson’s model failed to explain the results of later experiments, like Rutherford’s scattering experiment. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 29

Question 29: Thomson’s model visualizes the atom as:

A. A dense nucleus with electrons revolving around itB. A sphere with evenly distributed massC. A positively charged pudding with negative electrons embeddedD. A neutral particle with no internal structure

Answer

C. Thomson’s model visualizes the atom as a positively charged pudding with negative electrons embedded. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 30

Question 30: Which experiment led to the eventual discrediting of Thomson’s model?

A. Oil Drop ExperimentB. Rutherford’s Gold Foil ExperimentC. Millikan’s Oil Drop ExperimentD. Faraday’s Cathode Ray Discharge Experiment

Answer

B. Rutherford’s Gold Foil Experiment led to the eventual discrediting of Thomson’s Plum Pudding Model. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 31

Question 31: Rutherford’s Nuclear Model of the atom was based on which famous experiment?

A. Cathode Ray Tube ExperimentB. Gold Foil ExperimentC. Millikan’s Oil Drop ExperimentD. Photoelectric Effect Experiment

Answer

B. Rutherford’s Nuclear Model was based on the Gold Foil Experiment. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 32

Question 32: What was the major observation from Rutherford’s Gold Foil Experiment?

A. Most alpha particles passed through the foil with no deflection.B. Most alpha particles were deflected at large angles.C. Alpha particles bounced back directly from the foil.D. Alpha particles emitted light upon striking the foil.

Answer

A. Most alpha particles passed through the foil with no deflection, suggesting that most of the atom is empty space. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 33

Question 33: What did Rutherford conclude about the structure of the atom from his experiment?

A. Atoms consist mainly of empty space.B. Electrons are embedded within a sphere of positive charge.C. Protons and electrons are evenly distributed within the atom.D. Neutrons and protons are the same particles.

Answer

A. Rutherford concluded that atoms consist mainly of empty space, with a small, dense nucleus. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 34

Question 34: In Rutherford’s model, the nucleus is described as:

A. Large and positively chargedB. Small and neutrally chargedC. Dense and positively chargedD. Large and negatively charged

Answer

C. The nucleus is described as small, dense, and positively charged. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 35

Question 35: Which of the following is NOT a conclusion of Rutherford’s experiment?

A. The atom is mostly empty space.B. The nucleus contains protons and neutrons.C. The nucleus is positively charged.D. Electrons move around the nucleus in circular orbits.

Answer

B. Rutherford’s experiment did not lead to the discovery of neutrons; they were discovered later by Chadwick. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 36

Question 36: Rutherford’s model was unable to explain which of the following?

A. The existence of the atomic nucleusB. The arrangement of electrons around the nucleusC. The mass of the protonD. The existence of neutrons

Answer

B. Rutherford’s model was unable to explain the arrangement of electrons around the nucleus. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 37

Question 37: What feature of Rutherford’s model resembles the solar system?

A. The electrons are stationary around the nucleus.B. The nucleus plays the role of the Sun, and the electrons revolve like planets.C. The atom is filled with dense matter.D. Neutrons act like planets revolving around protons.

Answer

B. Rutherford’s model resembles the solar system, with the nucleus as the Sun and electrons revolving like planets. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 38

Question 38: The atomic number of an element is defined as the number of:

A. Electrons in an atomB. Protons in the nucleusC. Neutrons in the nucleusD. Nucleons in the nucleus

Answer

B. The atomic number is defined as the number of protons in the nucleus of an atom. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 39

Question 39: What does the mass number of an atom represent?

A. The number of protonsB. The number of neutronsC. The total number of protons and neutronsD. The total number of electrons

Answer

C. The mass number represents the total number of protons and neutrons in the nucleus. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 40

Question 40: Isobars are atoms with:

A. The same number of protons but different numbers of neutronsB. The same mass number but different atomic numbersC. The same number of electrons but different mass numbersD. Identical atomic numbers and mass numbers

Answer

B. Isobars are atoms with the same mass number but different atomic numbers. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 41

Question 41: Isotopes of an element differ in the number of:

A. ProtonsB. ElectronsC. NeutronsD. Nucleons

Answer

C. Isotopes of an element differ in the number of neutrons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 42

Question 42: Which theory explains the wave nature of light?

A. Bohr’s TheoryB. Planck’s Quantum TheoryC. Maxwell’s Electromagnetic TheoryD. Rutherford’s Nuclear Theory

Answer

C. Maxwell’s Electromagnetic Theory explains the wave nature of light. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 43

Question 43: What is the speed of light in a vacuum?

A. 3.0 × 10⁶ m/sB. 3.0 × 10⁸ m/sC. 6.022 × 10²³ m/sD. 9.11 × 10⁻³¹ m/s

Answer

B. The speed of light in a vacuum is 3.0 × 10⁸ m/s. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 44

Question 44: The relationship between frequency (ν), wavelength (λ), and speed of light C. is given by which equation?

A. E = mc²B. c = νλC. F = maD. P = IV

Answer

B. The relationship between frequency, wavelength, and the speed of light is given by the equation c = νλ. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 45

Question 45: Electromagnetic radiation consists of:

A. Oscillating electric and magnetic fieldsB. Pure energy with no chargeC. Charged particlesD. Neutral particles

Answer

A. Electromagnetic radiation consists of oscillating electric and magnetic fields. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 46

Question 46: Which part of the electromagnetic spectrum is visible to the human eye?

A. InfraredB. Radio wavesC. UltravioletD. Visible light

Answer

D. The visible light portion of the electromagnetic spectrum is visible to the human eye. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 47

Question 47: Planck’s Quantum Theory proposed that energy is:

A. ContinuousB. QuantizedC. InfiniteD. Constant

Answer

B. Planck’s Quantum Theory proposed that energy is quantized, meaning it comes in discrete amounts. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 48

Question 48: The smallest unit of electromagnetic energy, according to Planck, is called a:

A. PhotonB. ElectronC. ProtonD. Neutron

Answer

A. The smallest unit of electromagnetic energy is called a photon. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 49

Question 49: Which experiment demonstrated the particle nature of light by ejecting electrons from a metal surface?

A. Rutherford’s Gold Foil ExperimentB. Millikan’s Oil Drop ExperimentC. Photoelectric EffectD. Cathode Ray Tube Experiment

Answer

C. The Photoelectric Effect demonstrated the particle nature of light by ejecting electrons from a metal surface. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 50

Question 50: Who provided the explanation of the photoelectric effect using Planck’s Quantum Theory?

A. J.J. ThomsonB. Albert EinsteinC. Niels BohrD. James Chadwick

Answer

B. Albert Einstein explained the photoelectric effect using Planck’s Quantum Theory. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 51

Question 51: The energy of a photon is related to its:

A. Wavelength and speedB. Frequency and speedC. Mass and velocityD. Frequency and wavelength

Answer

D. The energy of a photon is related to its frequency and wavelength. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 52

Question 52: Which of the following statements about the photoelectric effect is true?

A. The energy of the ejected electrons depends on the intensity of light.B. No electrons are emitted below a certain threshold frequency.C. All metals have the same threshold frequency.D. Electrons are emitted regardless of the light frequency.

Answer

B. No electrons are emitted below a certain threshold frequency, specific to each metal. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 53

Question 53: Emission spectra occur when:

A. Atoms absorb energy and move to a higher energy stateB. Atoms release energy and return to a lower energy stateC. Atoms collide and produce soundD. Atoms are neutralized

Answer

B. Emission spectra occur when atoms release energy and return to a lower energy state. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 54

Question 54: Which series of lines in the hydrogen spectrum corresponds to visible light?

A. Lyman seriesB. Balmer seriesC. Paschen seriesD. Brackett series

Answer

B. The Balmer series corresponds to the visible light region of the hydrogen spectrum. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 55

Question 55: Which element was first discovered through its spectrum in the Sun?

A. HydrogenB. HeliumC. NitrogenD. Oxygen

Answer

B. Helium was first discovered through its spectrum in the Sun. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 56

Question 56: The Rydberg formula is used to predict the wavelengths of:

A. Radio wavesB. Infrared radiationC. X-raysD. Hydrogen spectral lines

Answer

D. The Rydberg formula is used to predict the wavelengths of hydrogen spectral lines. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 57

Question 57: Which of the following statements is true regarding atomic line spectra?

A. They are continuous and show all wavelengths of light.B. Each element has a unique line spectrum.C. All elements emit the same lines in their spectra.D. Line spectra can only be observed in solid elements.

Answer

B. Each element has a unique line spectrum. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 58

Question 58: What does a line spectrum indicate about the energy levels in an atom?

A. Energy levels are continuous.B. Energy levels are quantized.C. Atoms contain no energy.D. Atoms have infinite energy levels.

Answer

B. A line spectrum indicates that energy levels in an atom are quantized. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 59

Question 59: In which part of the electromagnetic spectrum does the Lyman series of hydrogen spectral lines appear?

A. Visible regionB. Ultraviolet regionC. Infrared regionD. Radio wave region

Answer

B. The Lyman series of hydrogen spectral lines appears in the ultraviolet region. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 60

Question 60: The Paschen series of hydrogen spectral lines appears in which region?

A. Visible regionB. Infrared regionC. Ultraviolet regionD. X-ray region

Answer

B. The Paschen series appears in the infrared region. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 61

Question 61: Who first observed and studied the line spectrum of hydrogen?

A. Albert EinsteinB. Niels BohrC. Johann BalmerD. James Chadwick

Answer

C. Johann Balmer first observed and studied the line spectrum of hydrogen. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 62

Question 62: What is the significance of the Rydberg constant in atomic spectra?

A. It is used to calculate the energy of protons.B. It helps predict the wavelengths of hydrogen spectral lines.C. It determines the mass of an electron.D. It defines the velocity of light in a vacuum.

Answer

B. The Rydberg constant is used to predict the wavelengths of hydrogen spectral lines. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 63

Question 63: According to Bohr’s Model, the electron in a hydrogen atom moves in:

A. Random orbitsB. Fixed circular orbitsC. Elliptical orbitsD. Stationary positions

Answer

B. According to Bohr’s Model, the electron in a hydrogen atom moves in fixed circular orbits around the nucleus. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Question 64

Question 64: Bohr’s model of the atom is based on which of the following concepts?

A. Electrons are stationaryB. Energy levels are continuousC. Electrons exist in quantized orbitsD. Electrons do not interact with the nucleus

Answer

C. Bohr’s model is based on the concept that electrons exist in quantized orbits around the nucleus. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The energy of an electron decreases as it moves closer to the nucleus, not increases. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The energy absorbed or emitted during a transition is equal to the difference between the energies of the two levels. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. Bohr’s model assumes that electrons do not radiate energy while in stable orbits, explaining the stability of the atom. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. A limitation of Bohr’s Model is that it applies only to atoms with one electron, such as hydrogen. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. In Bohr’s model, the energy of the electron in the nth orbit is inversely proportional to n². (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. The energy of the electron in the first orbit of hydrogen (n = 1) is –2.18 × 10⁻¹⁸ J. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. In Bohr’s Model, the ground state refers to the electron being in the first orbit (n = 1). (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. Bohr’s model can be applied to hydrogen-like ions such as He⁺ and Li²⁺. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. For hydrogen-like ions, the energy of the electron in the nth orbit is directly proportional to Z². (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The radius of the electron orbit in hydrogen-like ions is inversely proportional to Z. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. The energy levels for hydrogen-like ions are given by the expression Eₙ = –2.18 × 10⁻¹⁸ Z/n². (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. Louis de Broglie proposed the wave-particle duality of matter. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The Heisenberg Uncertainty Principle states that the exact position and momentum of a particle cannot be simultaneously determined. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. According to the de Broglie hypothesis, the wavelength of a particle is inversely proportional to its mass. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The de Broglie wavelength is significant for subatomic particles, such as electrons. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The principal quantum number defines the size and energy of an orbital. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The azimuthal quantum number determines the shape of an orbital. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. For a given principal quantum number (n), the possible values of the azimuthal quantum number (l) range from 0 to n-1. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The magnetic quantum number represents the orientation of the orbital in space. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. For an s-orbital, the azimuthal quantum number (l) is 0. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The p-orbitals have 3 possible orientations. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The spin quantum number (mₛ) has the possible values +½ or –½. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The p-orbital has a dumbbell shape. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The maximum number of electrons that can occupy an orbital is 2. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. The Aufbau principle states that electrons are added to orbitals in order of increasing orbital energy. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The Pauli Exclusion Principle states that no two electrons in the same atom can have the same set of quantum numbers. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. Hund’s Rule of Maximum Multiplicity states that electrons must occupy orbitals singly before pairing. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. According to Hund’s Rule, the electrons will occupy each p orbital singly (↑ ↑ ↑) before pairing. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The Aufbau principle explains that electrons occupy the most stable and lowest energy configuration. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

C. Hund’s Rule ensures that electrons in an atom minimize repulsion by occupying separate orbitals. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. The electronic configuration describes the arrangement of electrons in an atom’s orbitals. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. The electronic configuration of oxygen is 1s² 2s² 2p⁴. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. The electronic configuration of sodium is 1s² 2s² 2p⁶ 3s¹. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. Phosphorus has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p³. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

A. The element with atomic number 10 (neon) has the electronic configuration 1s² 2s² 2p⁶. (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Accepted Answer

B. Nitrogen (N) has a half-filled p-orbital in its ground state (1s² 2s² 2p³). (Structure of Atom Class 11 MCQ by Top100MCQ.com)

Structure of Atom Class 11 MCQ

1. Introduction to Atomic Theory (MCQ 1 to 8)

Early Philosophical Concepts of Atoms

Dalton’s Atomic Theory (1808)

Laws Explained by Dalton’s Theory

2. Discovery of Subatomic Particles (MCQ 9 to 26)

Discovery of Electron (MCQ 9 to 12)

Charge to Mass Ratio of Electron (J.J. Thomson) (MCQ 13 to 15)

Charge on the Electron (Millikan’s Oil Drop Experiment) (MCQ 16 to 18)

Discovery of Protons and Neutrons (MCQ 19 to 26)

3. Atomic Models (MCQ 27 to 41)

Thomson’s Plum Pudding Model (1898) (MCQ 27 to 30)

Rutherford’s Nuclear Model (1911) (MCQ 31 to 37)

Atomic Number and Mass Number (MCQ 38 to 41)

4. Developments Leading to Bohr’s Model (MCQ 42 to 62)

Electromagnetic Radiation (MCQ 42 to 46)

Particle Nature of Electromagnetic Radiation (MCQ 47 to 52)

Atomic Spectra (MCQ 53 to 62)

Bohr’s Model of Hydrogen Atom (1913) (MCQ 63 to 75)

Energy Levels of Hydrogen Atom (MCQ 69 to 71)

Applications to Hydrogen-Like Ions (MCQ 72 to 75)

6. Quantum Mechanical Model of Atom (MCQ 76 to 100)

Wave-Particle Duality (MCQ 76 to 79)

Quantum Numbers and Atomic Orbitals (MCQ 80 to 88)

Rules for Filling Orbitals (MCQ 89 to 94)

Electronic Configuration of Atoms (MCQ 95 to 100)

7. Most Asked Questions: Structure of Atom Class 11

What were the key observations from Rutherford’s Gold Foil Experiment?

How did Bohr’s Model explain the stability of the atom?

What is the Heisenberg Uncertainty Principle?

What is the significance of the quantum numbers in atomic structure?

What is the photoelectric effect and who explained it?

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