NEET Chemistry: Atomic Structure Practice Questions
15 free multiple-choice questions on Atomic Structure for NEET Chemistry, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more Atomic Structure questions in the app →Q1. Which of the following orbitals has a spherical shape?
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Correct answer: A — s orbital
The s orbital is spherical in shape, regardless of the principal quantum number (n).
Q2. According to the Bohr model, the angular momentum of an electron is quantized. This means that the angular momentum can only take values that are integral multiples of which quantity?
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Correct answer: A — Planck's constant
The angular momentum of an electron is quantized in terms of Planck's constant (h), leading to quantized orbits.
Q3. When an electron in a hydrogen atom transitions from a higher energy level to a lower energy level, the emitted radiation is characteristic of which type of spectral emission?
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Correct answer: A — Emission
When an electron falls from a higher energy state to a lower energy state, it releases energy in the form of a photon, which is defined as emission.
Q4. Consider the three p-orbitals (pₓ, p_y, p_z). If three electrons are placed in these orbitals, how should they arrange themselves according to Hund's rule?
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Correct answer: D — One electron in each orbital with the same spin.
According to Hund's rule, electrons will occupy the three degenerate orbitals singly first, with parallel spins, before any orbital is doubly occupied.
Q5. In a set of three degenerate orbitals (e.g., p-orbitals), how would the maximum multiplicity be achieved by electrons according to Hund's rule?
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Correct answer: C — One electron in each orbital with parallel spins.
To maximize multiplicity (and thus minimize energy), electrons must occupy separate orbitals with parallel spins.
Q6. The allowed stationary states for an electron in a hydrogen atom are defined by specific principal quantum numbers (n). Which of the following is the correct value for the minimum principal quantum number (n)?
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Correct answer: B — 1
For a stable orbit (stationary state) in the Bohr model of the hydrogen atom, the principal quantum number (n) must be a positive integer, meaning the minimum allowed value is 1.
Q7. If a system has a set of discrete energy values, it means the system can only occupy those specific energy states. This restriction is described by which quantum mechanical postulate?
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Correct answer: B — Quantization of energy levels
The restriction to specific, measurable energy values is the definition of energy quantization.
Q8. The relationship between the azimuthal quantum number (l) and the shape of an orbital is:
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Correct answer: B — l=0 corresponds to spherical shape
l=0 corresponds to s orbital (spherical), l=1 corresponds to p orbital (dumbbell), and l=2 corresponds to d orbital (more complex/cloverleaf).
Q9. Which of the following orbital shapes is perfectly spherical?
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Correct answer: A — s orbital
The s orbital is spherical in shape, meaning it has no angular dependence, unlike the directional shapes of p and d orbitals.
Q10. Which of the following statements is a fundamental postulate of the Bohr model for the hydrogen atom?
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Correct answer: C — The angular momentum of the electron is quantized.
The Bohr model postulates that the angular momentum of the electron is quantized (i.e., it can only take discrete values mvr = nħ), which leads to quantized energy levels.
Q11. According to the Aufbau principle, electrons are filled into orbitals in which order?
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Correct answer: C — n+l+m
The Aufbau principle states that electrons fill the lowest energy orbitals first, which is determined by the principle of increasing energy levels (n+l).
Q12. Which of the following statements accurately describes the nature of the de Broglie wavelength?
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Correct answer: B — It is the wavelength associated with the particle's momentum.
The de Broglie wavelength is fundamentally the wavelength associated with the particle's momentum (p), linking its particle properties to its wave properties.
Q13. Which of the following quantum numbers is used to describe the shape of an orbital?
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Correct answer: A — l
The azimuthal quantum number, 'l' (angular momentum quantum number), determines the shape of the orbital (s, p, d, f).
Q14. In an atomic system, the total spin of the system is the sum of the individual electron spins. If two electrons have spins s₁ = +1/2 and s₂ = -1/2, what is the possible value for the total spin quantum number S of the system?
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Correct answer: A — 1
The total spin is found by the vector addition of individual spins. The possible values for the total spin quantum number S are |s₁ - s₂|, |s₁ - s₂| + 1, …, s₁ + s₂. Here, S = 1/2 + (-1/2) = 0.
Q15. The spectral lines observed in the hydrogen atom are characteristic of transitions between discrete energy levels. This observation is a direct consequence of which fundamental principle in atomic structure?
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Correct answer: B — Quantization of Energy
The discrete nature of the spectral lines arises because the energy of the electron is quantized, meaning it can only exist in specific, discrete energy levels (Eₙ), as dictated by the quantization of energy.
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