They are suffixes used in polyatomic ions.
"Ite" refers to the lower state of oxidation and "ate" to the higher state.
Example: copper sulfite and copper sulfate
Hopefully I helped.
The ending -ate is used for the most common oxyanion of an element.
NO3- nitrate ion SO4-2 sulfate ion
The ending -ite is used for an oxyanion that has the same charge but one oxygen fewer
NO2- nitrite ion SO3-2 sulfite ion
They indicate oxy anions, with the ite having the lower oxidation number. Nitrite is NO2ˉ¹, and nitrate is NO3ˉ¹
Usually the suffix can represent the oxidation states of an atom within a polyatomic ion. '-ate' is when the oxidation number is higher; 'ite' is when it is lower.
For example, Nitrogen in NO3^-1 (Nitrate) the oxidation number is +5, and this is higher than the nitrogen's oxidation number in NO2^-1 (Nitrite), which has an oxidation number of +3.