Question

Calculate the percentage composition of zinc, phosphorus and oxygen in zinc phosphate, $Z{n_3}{\left( {P{O_4}} \right)_2}$.
($Zn = 65.5$, $P = 31$ and O = $O = 16$)

Answer 1

As we know that in chemistry, periodic tables play a vital role. In the periodic table there are totally $118$ elements. In the periodic table there are totally $18$ columns and $7$ rows. The columns are called groups. Hence, $18$ groups in the periodic table. The rows are called periods. Hence, totally $7$ period in the table. In the periodic table the seventeenth group is the halogen group. In this group, four elements are only considered as halogen out of five elements in the column. There are fluorine, chlorine, bromine and iodine considered as halogen in the modern periodic table. In the periodic table, $118$ different kinds of elements in different periods and different groups. Each element is not absolutely similar to the other element. Each and every element has a unique symbol.
Formula used:
The molecular weight of the molecule is nothing but the sum of atomic weight of the atom present in the molecule.
The weight percentage of the atom depends on the atomic weight of that atom and molecular weight.
${\text{The Weight Percentage Of The Atom = }}\dfrac{{{\text{the atomic weight of atom }}}}{{{\text{molecular weight}}}} \times {\text{100 }}$

Complete answer:
The atomic weight of zinc is $65.5$.
The atomic weight of oxygen is$16g$
The atomic weight of phosphorus is $31$.
The molecular weight of the molecule is nothing but the sum of atomic weight of the atom present in the molecule.
In zinc phosphate, three zinc atoms, eight oxygen atoms and two phosphorus atoms.
The molecular weight of zinc phosphate is calculate,
$= 3 \times 65.5 + 2 \times (31 + 16 \times 4)$
$= 386.5$
Hence the molecular weight of zinc phosphate is $386.5$.
The percentage composition of zinc in zinc phosphate is calculate,
The atomic weight of zinc is $65.5$.
$= \dfrac{{196.5}}{{386.5}} \times 100$
$= 50.84\%$
The percentage composition of zinc in zinc phosphate is $50.84\%$.
The percentage composition of oxygen in zinc phosphate is calculate,
The atomic weight of oxygen is $16g$
$= \dfrac{{128.}}{{386.5}} \times 100$
$= 32.12\%$
The percentage composition of oxygen in zinc phosphate is $32.12\%$.
The percentage composition of zinc in zinc phosphate is calculate,
The atomic weight of phosphorus is $31$.
$= \dfrac{{62}}{{386.5}} \times 100$
$= 16.04\%$
The percentage composition of phosphorus in zinc phosphate is $16.04\%$.

Note:
In general, modern periodic table ordering is based on the atomic number of the atoms. The lowest atomic number starting from the first and followed by a higher atomic number.
Depending on the energy level of the outermost shell in the atoms, periods are classified and place the atom in respect period. Depending on the electrons shielding and size and physical behaviour of the atom, groups are coming. The atomic number of the element is nothing but the number of electrons or number of protons. The mass number of the atom is nothing but the sum of the number of protons and number of neutrons. In general we move left to right metallic property of the atom decreases. We move right to left and non-metallic property decreases.