Question

Chromium is represented by the electronic configuration:

• A. $ \text{ }\!\![\!\!\text{ }Ne\text{ }\!\!]\!\!\text{ }3{{s}^{2}}\text{ }3{{P}^{6}}\text{ }3{{d}^{1}}\text{ }4{{s}^{2}} $
• B. $ \text{ }\!\![\!\!\text{ }Ne\text{ }\!\!]\!\!\text{ }3{{s}^{2}}\text{ }3{{p}^{6}}\text{ }3{{d}^{2}}\text{ }4{{s}^{1}} $
• C. $ \text{ }\!\![\!\!\text{ }Ne\text{ }\!\!]\!\!\text{ }3{{s}^{2}}\text{ }3{{p}^{6}}\text{ }3{{d}^{5}}\text{ }4{{s}^{1}} $
• D. $ ~[Ne]\text{ }3{{s}^{2}}\text{ }3{{p}^{6}}\text{ }4{{s}^{2}}\text{ }3{{d}^{4}} $

Answer 1

Answer: (C)

Atomic number of $ Cr=24 $ and its configuration is $ 1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{1}},3{{d}^{5}} $ or $ \text{ }\!\![\!\!\text{ }Ne\text{ }\!\!]\!\!\text{ }3{{s}^{2}},\text{ }3{{p}^{6}},\text{ }3{{d}^{5}},\text{ }4{{s}^{1}} $ because exactly full filled orbitals are more stable than nearly fulfilled orbitals.