The purpose of determining oxidation numbers is to identify the number of electrons that an atom has gained or lost in a compound. This helps in understanding the distribution of charges in a compound and predicting the reactivity of elements.
To determine the oxidation number of an atom in a compound, you need to follow a set of rules. These include assigning the oxidation number of a free element as 0, assigning the oxidation number of monatomic ions as their charge, and assigning a negative oxidation number to more electronegative atoms in a compound. You can then use algebra to solve for the oxidation number of the desired atom.
No, the oxidation number of an atom cannot be a fraction. It can only be a whole number or 0. This is because the concept of oxidation numbers is based on the transfer of electrons, which can only occur in whole numbers.
The oxidation number of a polyatomic ion is determined by considering the overall charge of the ion. The sum of the oxidation numbers of all the atoms in the ion must equal the charge of the ion. For example, in the sulfate ion (SO4) with a charge of -2, the oxidation number of sulfur would be +6, as the sum of the oxidation numbers of all the atoms (-2) must equal the charge of the ion (-2).
Oxidation number and valence electrons are related but different concepts. Oxidation number is a hypothetical charge that an atom would have if all its bonds were 100% ionic, while valence electrons are the electrons in the outermost energy level of an atom that are involved in chemical bonding. Oxidation numbers can change in different compounds, while valence electrons remain constant for an atom in a neutral state.