Scandium has the atomic number 21, which one will be its electronic configuration?
Correct answer: B. 1s2,2s2,2p6,3s2,3p6,4s2,3d1
- 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
This question appeared on the UHS MDCAT 2017 paper, which you can sit online with every answer explained.
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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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