Question

How do you write the name and formula of a binary compound?

Answer 1

For writing the formula of a given binary compound we have to know about the oxidation state of each species involved in the compound and for writing the name we have to follow the guidelines which are mentioned by the IUPAC.

Complete step by step answer:
As we know that binary compounds are those compounds which are formed by the combination of two types of atoms, and it is mainly divided into two types which are Ionic binary compounds and covalent binary compounds or molecular binary compounds.
Ionic binary compounds:-
- For writing the formula of ionic compound we will follow the given formula:
${\left( {{{\text{A}}^{\text{n}}}} \right)_{\text{m}}}{\left( {{{\text{B}}^{\text{m}}}} \right)_{\text{n}}}$
Where, ${\text{A}}$is a metal which shows positive oxidation state, ${\text{B}}$ is a non-metal which shows negative oxidation state, ${\text{n}}$ is the oxidation state of metal and ${\text{m}}$is the oxidation state of non – metal.
- And for writing the name we will follow following points:
- First we write the name of metal and then of non – metal without using Greek prefixes.
- At the end of the name of non–metal we will use the suffix ‘ide’ and whenever any metal shows more than one oxidation state then we will write its state by using roman numbers.
Example of ionic binary compounds with names are:
${\text{NaCl}}$ - Sodium Chloride
${\text{FeCl}}{}_3$ - Iron (III) Chloride
Covalent binary compounds or Molecular binary compounds:
- For writing the formula of covalent binary compounds we will follow the same formula:
${\left( {{{\text{A}}^{\text{n}}}} \right)_{\text{m}}}{\left( {{{\text{B}}^{\text{m}}}} \right)_{\text{n}}}$
Where, ${\text{A}}$ and ${\text{B}}$ both are non-metals, ${\text{m}}$ is the oxidation state of ${\text{A}}$ & ${\text{n}}$is the oxidation state of ${\text{B}}$.
- And for writing the name we will follow following points:
- Here also first we write the name of element ${\text{A}}$ and then of element ${\text{B}}$with the suffix ‘ide’.
- We will use Greek prefixes if any subscript is written in the formula.
Example of covalent binary compounds with names are:
${\text{N}}{{\text{F}}_{\text{3}}}$ - Nitrogen trifluoride
${{\text{H}}_{\text{2}}}{\text{O}}$ - Dihydrogen monoxide

Note: Here some of you may think that why we did not write subscript in ${\text{NaCl}}$, so the reason is that whenever subscript one or the same subscript is given we will not show them in formula.