Write the rules for assigning oxidation number.

1.	Write the rules for assigning oxidation number.
Answer» 1. All atoms in the elemental or molecular state have ‘zero’ oxidation state. 2. Elements of group I and II in the periodic table always have ‘+1’ and ‘+2’ oxidation states respectively. 3. Hydrogen ‘+1’ oxidation state in all its compounds except metal hydrides where it is ‘-1’ 4. Oxygen has been assigned an oxidation number of ‘-2’ in all its compounds except peroxides and oxygen fluoride. In peroxide it is ‘-1’ and in oxygen fluoride it is ‘+2’. 5. Halogens generally have ‘-1’ oxidation state. Except fluorine, other halogens may have positive oxidation states in their oxides and inter halogen compounds (Fluorine always has ‘-1’ state). 6. The algebraic sum of oxidation numbers of all the elements in a compound is zero and that in an ion is equal to the net charge on the ion.

Answer»

1. All atoms in the elemental or molecular state have ‘zero’ oxidation state.

2. Elements of group I and II in the periodic table always have ‘+1’ and ‘+2’ oxidation states respectively.

3. Hydrogen ‘+1’ oxidation state in all its compounds except metal hydrides where it is ‘-1’

4. Oxygen has been assigned an oxidation number of ‘-2’ in all its compounds except peroxides and oxygen fluoride. In peroxide it is ‘-1’ and in oxygen fluoride it is ‘+2’.

5. Halogens generally have ‘-1’ oxidation state. Except fluorine, other halogens may have positive oxidation states in their oxides and inter halogen compounds (Fluorine always has ‘-1’ state).

6. The algebraic sum of oxidation numbers of all the elements in a compound is zero and that in an ion is equal to the net charge on the ion.

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