FSc Part 1 Chemistry chapter 5: Atomic structure MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

30 exam-style questions on Atomic structure, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

30 questions · 3 topics · 10 per test

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What chapter 5 covers

Ten Atomic structure questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. In Rutherford's experiment, most α-particles passed straight through the gold foil. What did this show?

  1. A
    the nucleus is negatively charged
  2. B
    most of the atom is empty space
  3. C
    electrons are very heavy
  4. D
    the atom is a solid sphere of positive charge
Show answer

Answer: B. Only a very few α-particles were strongly deflected, so the positive charge and mass are concentrated in a tiny nucleus and the rest is mostly empty.

2. Heisenberg's uncertainty principle states that

  1. A
    the energy of an electron is quantised
  2. B
    no two electrons in an atom can have the same four quantum numbers
  3. C
    electrons fill orbitals of lowest energy first
  4. D
    the position and momentum of an electron cannot both be known exactly at the same time
Show answer

Answer: D. Δx × Δp ≥ h/4π: the more precisely position is known, the less precisely momentum is known. The other statements are Bohr, Pauli and Aufbau.

3. According to Bohr's model, the angular momentum of an electron in an allowed orbit is

  1. A
    nh/2π
  2. B
    h/2πn
  3. C
    nh/4π
  4. D
    2πnh
Show answer

Answer: A. Bohr's quantisation condition is mvr = nh/2π, where n = 1, 2, 3 ... . h/4π appears in Heisenberg's uncertainty principle.

4. Why do hydrogen atoms give a line spectrum rather than a continuous spectrum?

  1. A
    hydrogen has only one electron, so it gives only one line
  2. B
    electrons can only occupy orbits of fixed energy, so only certain energy differences are emitted
  3. C
    the atoms emit all frequencies of light equally
  4. D
    the protons emit the light
Show answer

Answer: B. Each line corresponds to a jump between two fixed energy levels, ΔE = hν. Hydrogen gives many lines because there are many possible jumps.

5. The lines of the hydrogen spectrum in the visible region belong to which series, and at which level do the transitions end?

  1. A
    Lyman, n = 1
  2. B
    Paschen, n = 3
  3. C
    Balmer, n = 2
  4. D
    Balmer, n = 1
Show answer

Answer: C. Balmer lines end at n = 2 and lie in the visible region. Lyman (ending at n = 1) is ultraviolet and Paschen (n = 3) is infrared.

6. Moseley showed that the square root of the frequency of the X-rays emitted by an element is proportional to its

  1. A
    atomic mass
  2. B
    atomic number
  3. C
    number of neutrons
  4. D
    group number
Show answer

Answer: B. √ν = a(Z − b): X-ray frequency depends on the nuclear charge, i.e. the atomic number. This is why the periodic table is based on atomic number, not mass.

7. What is the energy of a photon of frequency 5.0 × 1014 Hz? (h = 6.626 × 10−34 J s)

  1. A
    1.33 × 10−48 J
  2. B
    7.55 × 1047 J
  3. C
    3.31 × 10−19 J
  4. D
    3.31 × 10−20 J
Show answer

Answer: C. E = hν = 6.626 × 10−34 × 5.0 × 1014 = 3.31 × 10−19 J. Dividing h by ν gives the 10−48 value.

8. Using En = −1312/n2 kJ mol−1, what is the energy of an electron in the second orbit of hydrogen?

  1. A
    −328 kJ mol−1
  2. B
    −656 kJ mol−1
  3. C
    +328 kJ mol−1
  4. D
    −1312 kJ mol−1
Show answer

Answer: A. E2 = −1312 ÷ 22 = −328 kJ mol−1. Dividing by n (not n2) gives −656; the energy is negative because the electron is bound.

9. Millikan's oil drop experiment was used to determine

  1. A
    the e/m value of the electron
  2. B
    the mass of the proton
  3. C
    the charge on the nucleus
  4. D
    the charge on an electron
Show answer

Answer: D. Millikan found e = 1.602 × 10−19 C. J. J. Thomson had already measured e/m; combining them gives the mass of the electron.

10. What is the de Broglie wavelength of a 0.10 kg ball moving at 10 m s−1? (h = 6.63 × 10−34 J s)

  1. A
    6.63 × 10−32 m
  2. B
    6.63 × 10−34 m
  3. C
    6.63 × 10−36 m
  4. D
    1.51 × 1033 m
Show answer

Answer: B. λ = h/mv = 6.63 × 10−34 ÷ (0.10 × 10) = 6.63 × 10−34 m. It is far too small to detect, which is why wave nature matters only for tiny particles like electrons.

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Ways to practise this chapter

Atomic structure: questions students ask

How many Atomic structure MCQs are there?

30, each with the answer and a short explanation, across 3 topics: Discovery of subatomic particles and Rutherford's model, Planck's theory, Bohr's model and the hydrogen spectrum, Quantum numbers, orbitals and electronic configuration. Every chapter test draws ten of them, so you can take it many times.

Is the FSc Part 1 Chemistry chapter 5 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Can I read the explanations in Urdu?

Yes. In practice mode and on your results you can switch the explanations to Urdu.

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