NEET Chemistry: Electronic configuration of elements Practice Questions
15 free multiple-choice questions on Electronic configuration of elements (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 NEET questions in the app →Q1. 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).
Q2. The electrons that are involved in the chemical bonding of an atom are known as:
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Correct answer: A — valence electrons
Valence electrons are the electrons found in the outermost shell, which are responsible for chemical bonding and reactivity.
Q3. Which rule governs the arrangement of electrons in degenerate orbitals of the same energy level?
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Correct answer: A — Hund's Rule
Hund's rule states that electrons will fill orbitals within a subshell singly before pairing up, maximizing the total spin.
Q4. Which rule dictates that no two electrons in an atom can have the same set of four quantum numbers?
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Correct answer: A — Pauli exclusion principle
The Pauli exclusion principle states that no two electrons in an atom can have the identical set of four quantum numbers (n, l, mₗ, mₛ).
Q5. Which rule dictates the way electrons are distributed among orbitals within the same subshell?
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Correct answer: A — Hund's rule
Hund's rule states that electrons will singly occupy degenerate orbitals with parallel spins before pairing up, which governs the maximum multiplicity of an electronic configuration.
Q6. Which of the following statements is a direct consequence of the Pauli exclusion principle?
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Correct answer: D — No two electrons in an atom can have the same set of four quantum numbers.
The Pauli exclusion principle states that no two electrons in an atom can have the exact same set of four quantum numbers (n, l, m_l, m_s), meaning they must have opposite spins in the same orbital.
Q7. Which electronic configuration is correctly represented for the element Nitrogen (Atomic number 7)?
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Correct answer: C — 1s²2p¹
Nitrogen has 7 electrons. The filling order is 1s (2), then 2s (2), then 2p (3). The correct configuration is 1s²2s¹
Q8. The maximum number of electrons that can be placed in the d-subshell is:
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Correct answer: C — 14
The d-subshell corresponds to l=2, which means there are three d-orbitals. Since each orbital can hold a maximum of 2 electrons, the total capacity is 7 × 2 = 14 electrons.
Q9. Which orbital can hold a maximum of two electrons?
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Correct answer: A — 1s
The 1s orbital is a single orbital, and by the Pauli exclusion principle, it can hold a maximum of two electrons (with opposite spins).
Q10. Which of the following quantum numbers is used to describe the size and shape of an electron's orbital?
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Correct answer: B — l
The azimuthal quantum number (l) describes the shape of the orbital (subshell), while the principal quantum number (n) describes the energy level.
Q11. How many electrons can be accommodated in a p-subshell?
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Correct answer: D — 6
The principal quantum number l=1 corresponds to the p-subshell, which has three orbitals (mₗ = -1, 0, +1), and thus can hold a maximum of 2 × 3 = 6 electrons.
Q12. Which set of quantum numbers uniquely specifies the state of an electron in an atom?
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Correct answer: A — 3. Magnetic Quantum Number
The magnetic quantum number (mₗ) specifies the orientation of the orbital in space, along with the principal quantum number (n) and the azimuthal quantum number (l), which collectively define the state of an electron in an atom.
Q13. According to Hund's rule, the unpaired electrons in a set of degenerate orbitals will have:
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Correct answer: B — Parallel spins
Hund's rule states that electrons will occupy degenerate orbitals singly with parallel spins before pairing up.
Q14. According to the Aufbau principle, the order of filling for atomic orbitals is:
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Correct answer: C — 1s, 2s, 2p, 3s, 3p
The Aufbau principle dictates filling based on increasing energy levels. The correct order of filling is 1s, 2s, 2p, 3s, 3p, etc.
Q15. The electronic configuration of an element with atomic number 11 (Sodium) is:
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Correct answer: A — 1s²2s¹
Atomic number 11 means 11 electrons. Following the Aufbau principle: 1s² (2 e), 2s¹ (1 e). Total: 3 electrons remaining. 2p¹ (1 e). Configuration: 1s²2s¹2p¹ (or 1s²2s¹).
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