why some elements so variation in their oxidation number? And in such a case how to find its oxidation no if its is used in a rxn...
Dear student
Elements show variable oxidation state when they can loose both d as well as s electrons. So the loss of s electrons can lead to either +1 or +2 oxidation state and the loss of d electrons can lead to any positive oxidation number based upon the total number of electrons present in the d orbital. In order to find the variable oxidation state, you are advised to first write the electronic configuration and then try to find out how many d or s electrons can be lost.
If we take an example of iron, Fe has been found to be in +2 as well as +3 oxidation state. The electronic configuration of Fe is 3d64s2.
If Fe looses only the s electrons, Fe will get an oxidation state of +2. But Fe can also loose one more d electron in order to get the stable electronic configuration since now the d orbitals will be exactly half filled. So Fe gets +3 oxidation state also.
Regards
Elements show variable oxidation state when they can loose both d as well as s electrons. So the loss of s electrons can lead to either +1 or +2 oxidation state and the loss of d electrons can lead to any positive oxidation number based upon the total number of electrons present in the d orbital. In order to find the variable oxidation state, you are advised to first write the electronic configuration and then try to find out how many d or s electrons can be lost.
If we take an example of iron, Fe has been found to be in +2 as well as +3 oxidation state. The electronic configuration of Fe is 3d64s2.
If Fe looses only the s electrons, Fe will get an oxidation state of +2. But Fe can also loose one more d electron in order to get the stable electronic configuration since now the d orbitals will be exactly half filled. So Fe gets +3 oxidation state also.
Regards