Question

the electronic configuration of an element is [18 ar],4s2,3d4. this electronic configuration represents which element
a)Cr b)Al c)Mn d)Co

Answer 1

Answer: The answer is Chromium

Explanation:

In the case of chromium the expected electronic configuration is 4s2 3d4. But actually one electron from 4s gets transferred to 3d making it 4s1 3d5. This happens so because it is a more stable configuration. Actually the order of stability goes like this

Fully filled orbital > half filled orbital > incompletely filled orbital

So the configuration mentioned in the question is not correct one. The correct electronic configuration is 4s1 3d5 and it is of Chromium.

Answer 2

Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.