Question

Please explain the answer as well thx

How many d-electrons are there in the following species? Cut MnO2

Answer 1

Part A;

Atomic number of Cu is 29.

Electronic configuration of Cu is

[Ar] 3d¹⁰4s¹

So, to form Cu⁺ one electron is removed from 4s orbital.

Hence, electronic configuration of Cu⁺ is

[Ar]3d¹⁰ .

So, total number of d electrons in Cu⁺ = 10.

Part B;

In MnO₂ , as oxidation state of O = -2,

So, oxidation state Mn = +4

- Mn o 1 4 Мmo 04 MnO2

Now, atomic number of Mn = 25

Electronic configuration of Mn is

[Ar] 3d⁵4s²

To form Mn⁴⁺,  2 electrons are removed from 4s orbital and 2 electrons are removed from 3d orbital.

Hence, electronic configuration of Mn⁴⁺ is

[Ar] 3d³ .

Hence, total number of d electron in MnO₂ = 3

[ note: [Ar] = 1s²2s²2p⁶3s²3p⁶ ] .