Question

-ide and –ate, how do you know which one to use?

Answer 1

Hint: -ide and –ate both of these terms are used for the ions which are present in an anionic form i.e. in which negative charge or extra electrons are present as compared to the original atom.

Complete step by step answer:
 First we discuss about the term ‘–ide’ and points regarding this are as follow:
-The term ‘ide’ is used only for the non – metal monatomic ion or anion i.e. when any non –metal atom is singly present which bears negative charge then –ide is used as a suffix at the end of the name of the atom.
-Generally in ionic compounds after the name of the cation, the name of an anion will be placed which has ide as a suffix in its name.
For example: $\text{N}{\text{a}}^{+}\text{C}{\text{l}}^{-}$ - Sodium Chloride
${\text{K}}^{+}\text{C}{\text{l}}^{-}$ - Potassium Chloride
Now we will discuss about the term ‘-ate’ and points regarding this are as follow:
-The term ‘ate’ is used for polyatomic ion rather than the monatomic ion or anion i.e. when in the molecule more than one atom is present than in this condition if they bears a negative charge then -ate is used a suffix at the end of the name of that molecule.
For example: $\text{N}{{\text{O}}_3}^{-1}$ - Nitrate
$\text{S}{{\text{O}}_{\text{4}}}^{\text{2 - }}$ - Sulfate

Note: Here some you may think that why the name of $\text{O}{\text{H}}^{\text{ - }}\text{\& C}{\text{N}}^{\text{ - }}$ ion is hydroxide and cyanide respectively, in despite of having more than one atom. So the reason is that these two ions are exceptional in this nomenclature because during their discovery they were accepted as monatomic ions.