Number of unpaired electrons in boron in ground state is/are:
Correct answer: A. 1
- A. 1
- B. 2
- C. 3
- D. 4
Explanation
Boron has atomic number 5, so its configuration is 1s2 2s2 2p1 and the single 2p electron is the only unpaired one. The 1s and 2s electrons are paired within their orbitals. Boron's three valence electrons allow three bonds, but only one of them is unpaired in the ground state, which is the distinction being tested.
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About Electronic Configuration
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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