Hello Aspirant,

The 38 elements in groups 3 through 12 of the periodic table are called "transition metals". As with all metals, the transition elements are both ductile and malleable, and conduct electricity and heat. The interesting thing about transition metals is that their valence electrons, or the electrons they use to combine with other elements, are present in more than one shell. This is the reason why they often exhibit several common oxidation states.Oxidation occurs when a chemical reaction causes electrons to move.The oxidation state is the level of oxidation a substance has experienced and is expressed through an oxidation number.  There are three noteworthy elements in the transition metals family. These elements are iron, cobalt, and nickel, and they are the only elements known to produce a magnetic field.

Now coming to Iron,which is what your query is related to,the two most common ions, iron(II) Fe2+ (ferrous ion) and iron(III) Fe3+(ferric ion) both have electron configurations that include a partly filled 3d sub–shell.This is the most important criteria for considering whether such an element is a transition metal.The electron configurations are: Fe2+ is [Ar]3d6 and Fe3+ is [Ar]3d5.For both iron ions, there is at least one electron that can be promoted to a higher level when the 3d sub–shell is split as the central metal ion interacts and bonds with ligands.

Ferrous oxide contains iron that lost 2 elections in the oxidation process. So it is able to bond with other atoms that have an extra 2 electrons to share. Ferric oxide contains iron that lost 3 electrons and can take an extra 3 electrons bonding with other atoms. Each iron compounds have different nature and purposes.

Ferrous oxide comes as a black powder and, surprisingly, contains ferric oxide. It is used to produce numerous materials like plastics, heat-absorbing glass, paper, ceramics, and even rubber. Special high purity iron oxides are used to produce a type of ceramic magnet called ferrites, used in electronics like speakers, TVs, and computer memory cores.

Ferric oxide, also known as hematite, is a reddish-brown powder. It is FDA approved for cosmetic use, even around the eyes. But ferric oxide is most helpful in the iron and steel industries. It is the primary source for the iron used to create the entire industrialized world.

All the best