Question

why does cr and cu have different configurations​

Answer 1

Answer:

The order of filling of electrons occupying the 3d subshell gets concerned in chromium and copper and because of distress in 3d subshell, these elements possess exceptional configuration.

Explanation:

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Answer 2

Answer:

We know that electronic configuration is based on the Aufbau principle.

The order of filling of electrons occupying the 3d subshell gets concerned in chromium and copper and because of distress in 3d subshell, these elements possess exceptional configuration.

In Cr we can see that last d orbital is having 4 electrons in outermost shell to to attain stability it should have at least 5 electrons in its d subshell so it will take 1 electron from s subshell and now Cr will be more stable in its new electronic configuration.

Same happens with Cu. We can see that in Cu d subshell has 9 electrons so to become stable it needs 1 more electron in d subshell so it will take 1 electron from s subshell and now Cu will become stable in its new electronic configuration.

Hence, Cr and Cu are called exceptional configuration.

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