[pluvam (OP)]

I know that the answer lies in their electron configurations but what exactly?

For example Fe, Fe(+2) and Fe(+3)

And also how do i know which oxidation number is the most common for any transition metal?

Thanks for any help

[Chemistry4me]

The various oxidation states correspond to the involvement of the 4s and unpaired 3d electrons in transition metals. For example, Mn has 5 unpaired 3d electrons and two 4s electrons. It's highest oxidation state is +7 when it uses all seven of these electrons. Then there is Mn²⁺ which is +2 and it has lost the two 4s electrons. In between all theses you have, MnCl₂ (+2), Mn₂O₃ (+3), MnO₂ (+4), +5 can't think of one [], and MnO₄^2- (+6). There is also +1 which is not very common. All of these have different numbers of electrons involved in bonding hence the different oxidation states.

[yor_on]

nice explanation.
Ah, just what is transition metal's?

[EvilFrog]

transition metals are the elements in between group 2 to group 3(i mean between the group that start with Be to the group that start with B). can i say like that? Is it an explanation?

[yor_on]

Possibly

But chemistry is a field if its own