Question

How do you find the oxidation number and the coordination number?

Answer 1

Hint: The oxidation number of a compound or an ion is the charge of that specific ion which it possesses.
It results because of the presence of extra electrons, which corresponds to negative oxidation state, or the absence of electrons, which corresponds to the positive oxidation state.
The coordination number of a species cannot be negative, it could only be positive whole numbers as it gives us the idea of the number of elements to which a species is interacting, simultaneously.

Complete step-by-step answer:
The oxidation number can be defined as the number which tells us whether the species is a cation or an anion. It is an important factor of a species because it also gives us the information about the nature of the species. For instance, if a species has a negative oxidation state or oxidation number, it tells us that it is capable of binding with the species having positive oxidation number. The species with negative oxidation number are also capable of donating their electrons because of the abundance of electrons, and so they could also be termed as bases, while the positive ions could also be termed as acids, because of their electron attracting tendencies.

Let us consider an example of a species for better understanding. Consider the species ${[Ag{(CN)}_2]}^{-}$, the oxidation number of the whole compound is $-1$. As the individual oxidation numbers of the elements involved in the compound is $+1$ and $-1$ for silver and cyanide ions respectively.

Now consider the definition of the coordination number which is the number of elements of a molecule to which the central atom or the central ion is interacting all at once. Meaning, if we take the same example of ${[Ag{(CN)}_2]}^{-}$ the coordination number of silver ion is two, because it is interacting with two cyanide ions at once.

Note: Inside the coordination sphere, the coordination number is the number of species with which the central atom or the central ion is interacting all at once.
Whereas, the oxidation number is the total charge which is shown by a molecule or an ion, which is generated because of the gain or loss of electrons.