Free Electronic Configuration MCQs with Answers
103 Electronic Configuration MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Electronic configuration describes how electrons occupy shells, subshells and orbitals around an atom. Questions use the Aufbau principle, Pauli exclusion principle and Hund's rule to write configurations, identify valence electrons, form ions and explain periodic trends, including common exceptions such as chromium and copper.
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103 questions · page 4 of 6
- A. Aufbau Principle
- B. n + l rule
- C. Hund's rule
- D. Pauli exclusion principle
Explanation: Hund's rule explains the electronic configuration of degenerate orbitals
Correct answer: Hund's rule- A. Li+2
- B. H+
- C. He+
- D. Be
Explanation: The charge to mass ratio is called the e/m ratio. e/m ratio is a physical quantity, widely used in the electrodynamics of charged…
Correct answer: Be- A. 18
- B. 10
- C. 17
- D. 8
Explanation: Option A: This option suggests that the chloride ion (Cl-) has 18 valence electrons. However, this is incorrect.
Correct answer: 8- A. 2(l+1)
- B. l+1
- C. n+l
- D. 2(n+l)
Explanation: The arrangement of subshells or orbitals within an atom is based on the principle known as the Aufbau principle.
Correct answer: n+l- A. 50
- B. 49
- C. 48
- D. 44
Explanation: No. of (proton=electron)=(atomic no.)No. of neutron=Atomic no. - no. of protonIn case of H2SO4,H2 = 2 protons & 2electronS = 16…
Correct answer: 48- A. 24
- B. 5
- C. 72
- D. 98
Explanation: Calculate this by using the 2n2 formula. In the formula 2n², n = 7 so 2(7)², 2(49), "98".
Correct answer: 98- A. Half filled subshell
- B. Completely filled subshell
- C. Partially filled subshell
- D. Bought Options A and B are correct
Explanation: As per Hund's rule, atoms with half-filled or completely-filled orbitals are comparably more stable, so removing an electron from such…
Correct answer: Bought Options A and B are correct- A. Number of electrons
- B. Number of Unpaired electrons
- C. Number of Paired electrons
- D. Number of Protons
Explanation: Melting point: The constant temperature at which a solid changes into liquid is called melting point.
Correct answer: Number of Unpaired electrons69. The maximum number of electron accommodated in a shell or energy level is calculated by formula _.
- A. n2
- B. 2n2
- C. 2n
- D. 3n
Explanation: Option BThe number of electrons accommodated in an orbit is given by 2n2.
Correct answer: 2n2- A. Electronic configuration
- B. Ionic size
- C. Reactivity
- D. pH
Explanation: Isoelectronic species are atoms, ions, or molecules that have the same number of electrons and therefore the same electronic…
Correct answer: Electronic configuration- A. beings-block elements
- B. inert gas configurations
- C. ns1 electronic configuration
- D. being metals
Explanation: Second ionization energy can be defined as the removal of one mole of electron from the one mole of monovalent gaseous cation of the…
Correct answer: inert gas configurations- A. [He] 2s1
- B. [Ne] 3s1
- C. [Ne] 3s2
- D. [He] 2s2
Explanation: Option A) [He] 2s1 is incorrect because the electronic configuration of helium (He) has only two electrons in its 1s orbital, and…
Correct answer: [Ne] 3s1- A. [Ar] 4s23d4
- B. [Ar] 4s23d5
- C. [Ar] 4s13d4
- D. [Ar] 4s13d5
Explanation: The atomic number of Cr is 24. Its electronic configuration is as follows;[Ar]4s13d5If we follow the AufBau principle, it should have been…
Correct answer: [Ar] 4s13d5- A. 8
- B. 32
- C. 18
- D. 25
Explanation: The maximum number of electron that can accommodate in a shell is given by the formula 2n2.
Correct answer: 18- A. Half filled subshell
- B. Completely Filled Subshell
- C. Partially filled subshell
- D. Both A and B
Explanation: Half-filled subshells and completely filled subshells have a symmetrical distribution of electrons e.g. p3 or p6.
Correct answer: Both A and B- A. Increases.
- B. Decreases.
- C. Remains constant.
- D. Decreases then increases.
Explanation: Paramagnetism is due to the presence of unpaired electrons in the material, so most atoms with incompletely filled atomic orbitals are…
Correct answer: Increases.- A. 1s2,2s2,2p6,3s2,3p6,3d3
- B. 1s2,2s2,2p6,3s2,3p6,4s2,3d1
- C. 1s2,2s2,2p6,3s2,3p6,4s2,4p1
- D. 1s2,2s2,2p6,3s2,3p6,4s1,4p2
Explanation: The electronic configuration for Sc is 1s2, 2s2, 2p6, 3s2, 3p6 and since 4s is filled before 3d, we get 4s2 and 3d1
Correct answer: 1s2,2s2,2p6,3s2,3p6,4s2,3d1- A. 28
- B. 29
- C. 30
- D. 34
Explanation: No of electrons = no of protons = atomic number in a neutral atom. Since Ga-69 has atomic number 31 so its number of electrons is also 31…
Correct answer: 28- A. Ferromagnetic
- B. Diagmagnetic
- C. Electromagnetic
- D. Paramagnetic
Explanation: A ferromagnetic substance, like iron, retains magnetic properties after removing the field.
Correct answer: Paramagnetic- A. Mg
- B. He
- C. Fe
- D. Ne
Explanation: Isoelectronic species have the same number of electrons. In this case, Na+ has 10 electrons after losing one to become an ion.
Correct answer: Ne