Manipal MET2016Chemistryd and f Block Elements
The electronic configurations of chromium (at. no. 24) and copper (at. no. 29) are
Options
- A[ Ar ] 4 s^1 3 d^5 and [ Ar ] 4 s^1 3 d¹⁰
- B[ Ar ] 4 s^2 3 d^4 and [ Ar ] 4 s^1 3 d¹⁰
- C[ Ar ] 4 s^1 3 d^5 and [ Ar ] 4 s^2 3 d^9
- D[ Ar ] 4 s^2 3 d^4 and [ Ar ] 4 s^2 3 d^9
Correct answer
A. [ Ar ] 4 s^1 3 d^5 and [ Ar ] 4 s^1 3 d¹⁰
Step-by-step solution
Chromium and copper have five and ten electrons in 3 d -orbitals rather than four and nine because fully-filled and half-filled orbitals have lower energy and thus have extra stability. Therefore, chromium and copper have d^5 and d¹⁰ -configurations.