An element M with an electronic configuration of 1S2 2S2 2P6 3S2 3P6 4S2 3D6 has oxidation states of

 An element M with an electronic configuration of 1S2 2S2 2P6 3S2 3P6 4S2 3D6 has oxidation states of 

A. +1 only.

B. +1 and +2.

C. +2, +3 and +6.

D. +3 and +4.

E. +3, +4 and +5

The correct answer is C. +2, +3 and +6.

Explanation: When you add all the electrons from the electronic configuration together you will get

2+2+6+2+6+2+6= 26 electrons

Also recall that the number of electrons in an atom correspond to the number of protons commonly called atomic number.

You will realize that this correspond to iron with the atomic number of 26.

Iron exhibit +2, +3 and +6 oxidation states in certain compounds.

The +2 oxidation state is known to give greenish colouration to compounds containing them.

The +3 oxidation state is known to give brown colouration to compounds containing them.

While the +6 oxidation state is found rare in nature.

The other options are incorrect because element M is a transition element known for thier variable oxidation state and for the fact that they are d-block element. The d-block element have five sub orbitals dx2-y2, dz2,dxy, dyz, dxz.

QUESTION SOURCE: NECO CHEMISTRY 2001 QUESTION 33