Sodium-11 has the electronic configuration:
Correct answer: B. [Ne] 3s1
- 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 Sodium-11 has more than two electrons.Option B) Electronic configuration of sodium is 1s2 2s2 2p6 3s1, whereas the electronic configuration of neon is 1s22s2 2p6. Therefore the electronic configuration of sodium can be written as [Ne] 3s1 Option C) INe1 3s2 is incorrect because the element with the atomic number 11 is sodium (Na), not iodine (I), which has an atomic number of 53.Option D) [He] 2s2 is incorrect because this is the electronic configuration of helium-like ions, which have lost one electron, and Sodium-11 is a neutral atom with all its electrons.
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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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