What is the cesium phosphate formula?

Hint: Attempt this question by breaking the given compounds into parts and write down the elemental notation for each of them. Then, write them altogether to get the formula of the given compound. As we are given cesium phosphate in the question, so it can be broken down into cesium ion and phosphate ion to get our answer easily.

Complete answer:
As we know that cesium phosphate can be broken into cesium ion and phosphate ion. So let us study about them and gather their chemical formulas to get our answer as follows:-
Cesium: It is an element with the symbol Cs and belongs to group-1 of s-block with atomic number 55. It is a grey-golden alkali metal with a melting point of about 28.5${}^\circ C$that makes it one of the five elemental metals that are liquid at or near room temperature. Cesium has physical and chemical properties similar to those of potassium and rubidium.
-Since the valency of Cesium element is +1, so the chemical formula for cesium ion = $C{{s}^{+1}}$.
Phosphate: The phosphate ion consists of a central phosphorus atom surrounded by four oxygen atoms in a tetrahedral arrangement and is the conjugate base of the hydrogen phosphate ion $HP{{O}_{4}}^{-2}$.
-The chemical symbol for phosphate ion is: $P{{O}_{4}}^{-3}$
-By the above data we may conclude that for each $P{{O}_{4}}^{-3}$ion we require three $C{{s}^{+1}}$ ions to complete its octet and hence the chemical formula for cesium phosphate is $C{{s}_{3}}P{{O}_{4}}$

Note:
-Remember that the phosphate compounds of alkali metals are generally soluble in water and since cesium is an alkali metal, so cesium phosphate is highly soluble in water.
-Also try to study and learn the group wise valencies of each element.