Answer to Question #286212 in Inorganic Chemistry for Mapo

Question

Transition element

a) give the full electronic configuration of the copper atom ?

b) explain why some copper(I) are colourless yet most copper(II) compounds are coloured?

c ) complete the following electron configurations.

(I) Cu 1s2 2s2 2p6 3s2 3p6 ….

(II) Cu+2 1s2 2s2 2p6 3s2 3p6 ….

Answer 1

(a)

$1s^2\>2s^2\>2p^6\>3s^2\>3p^6\>3d^{10}\>4s^1$

(b)

The color exhibited by copper(ii) compounds is due to d-d transition

In case of $Cu^{+2}$ , the outermost electronic configuration is $3d^9$ .An electron in its valency shell absorbs radiation of visible region and get excited to emit its complimentary colour.

The outer electronic configuration for $Cu^+$ is $3d^{10}$ making the d-orbitals fully filled with no unpaired electron. There is no space for electron to jump to, and therefore no absorption of energy takes place.

c(i)

$Cu;$ $1s^2\>2s^2\>2p^6\>3s^2\>3p^6\>3d^{10}\>4s^1$

c(ii)

$Cu^{2+};[Ar]3d^9$