Question

What is the oxidation number for iron?

Answer 1

Hint :We know that the oxidation number of any atom of the molecule depends upon its combining capacity and/or valency; but is calculated by simple mathematical calculations. The calculations depend upon the overall charge on the molecule completely.

Complete Step By Step Answer:
Let us learn about the calculations based on the oxidation number; when we say that the calculations are based on the overall charge on the molecule; we have three possibilitiesCharge is zero i.e. neutral molecule. Charge is positive i.e. cationic molecule. Charge is negative i.e. anionic molecule.
The degree of oxidation for an atom in a chemical compound is determined by its oxidation state; it's an experimental or imaginary charge that an atom would have in the case that if all bonds to atoms of various elements were completely ionic. Oxidation states are typically represented by integers, which might be positive, negative, or zero. Let us get to know about the oxidation number of some elements.
Here to calculate oxidation number we will take compound $ F{{e}_{2}}{{O}_{3}} $
A neutral molecule i.e. $ F{{e}_{2}}{{O}_{3}} $ and we know the charge on Oxygen is $ -2. $ Thus,
 $ (2\times x)+(3\times (-2))=0 $
On further solving we get;
 $ \Rightarrow 2x-6=0 $
 $ \Rightarrow 2x=6 $
 $ \Rightarrow x=+3 $
Thus the oxidation number of iron here is $ +3. $
The most common oxidation numbers of $ ~Fe~ $ are $ +2 $ , as in $ FeC{{l}_{2}} $ , and $ +3 $ , as in $ FeC{{l}_{3}},F{{e}_{2}}{{O}_{3}} $ . Compounds are known in which iron has other oxidation numbers, but they are relatively unimportant at this level of study.

Note :
Remember that Oxidation state of an element or an atom is the number which can be negative, positive or zero. It also can be any integer. It indicated how many electrons are lost, or gained, in an atom. Oxidation results in the increase of oxidation number where reduction results in the decrease of oxidation number.