Electronic configuration of chromium (proton number 24) is:
Correct answer: C. [Ar] 3d5 4s1
- A. [Ar] 3d4 4s2
- B. [Ar] 3d2 4s2
- C. [Ar] 3d5 4s1
- D. [Ar] 3d5 4s2
Explanation
Chromium(Cr) and Copper(Cu) are two special cases in which electron from 4s orbital jumps to 3d so 4s orbital has only a single electron in it. In options there is only one option that has a single electron in 4s orbital which is C. A is a wrong form to write Cr electronic configuration because technically when 3d has 4 electrons a single electron will jump from 4s to 3d to make it 5 in 3d, as it is a more stable state. B and D cannot be right because they correspond to electronic configuration of atoms having a proton number 25.
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About Transition Elements
Transition elements are identified by their partially filled d subshells in atoms or common ions. The topic covers the electronic structure of d-block elements, including the filling order of 4s and 3d orbitals, variable oxidation states and the distinction between transition elements and elements with completely filled d subshells.
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