Question

Calculate‌ ‌the‌ ‌number‌ ‌of‌ ‌atoms‌ ‌of‌ ‌each‌ ‌element‌ ‌present‌ ‌in‌ ‌the‌ ‌compound,‌ ‌Name‌ ‌the‌ ‌elements‌ ‌and‌ ‌write‌ ‌the‌ ‌total‌ ‌number‌ ‌of‌ ‌elements‌ ‌present‌ ‌in‌ ‌it.‌ ‌
(i)Calcium‌ ‌phosphate‌ ‌
(ii)Ammonium‌ ‌phosphate.‌ ‌
(iii)Sodium‌ ‌acetate‌ ‌

Answer 1

The number of atoms of an element are present in a fixed proportion by mass. The number of elements are present in a definite number for a compound. For a compound such as ${M_x}{N_y}$ the subscript to the bottom and right gives us the number of atoms of that element.

Complete step-by-step answer: We know that in a chemical formula the symbols for each element in the compound are followed by subscripts that tell us how many elements are present in the compound.
For calcium phosphate the chemical formula is $C{a_3}{(P{O_4})_2}$ . Here the subscripts that follow each element indicate how many of that element are present in the compound. Here for one molecule of calcium phosphate , we can see that there are three atoms of calcium(Ca), two atoms of phosphorus, eight atoms of oxygen. The name of the elements present are calcium, phosphorus and oxygen and the total number of elements are three.
Similarly for ammonium phosphate the chemical formula is ${(N{H_4})_3}P{O_4}$. Here for one molecule of ammonium phosphate ,we can see that there are three atoms of nitrogen(N), twelve atoms of hydrogen(H), one atom of phosphorus, four atoms of oxygen. The name of the elements present are nitrogen, hydrogen, phosphorus and oxygen and the total number of elements is four.
Similarly for sodium acetate the chemical formula is $C{H_3}COONa$ . Here we can see that there are two atoms of carbon(C), three atoms of hydrogen(H), two atoms of oxygen(O) and one atom of sodium(Na). The name of elements present are carbon, hydrogen, oxygen and sodium and the total number of elements is four.

Note: The law of definite proportions is the main thing behind this concept. It emphasises on the fact that every compound has a fixed formula with its component element always occurring in the same ratio to one another.