Question

What is the atomicity of ${P_4}{O_{10}}$ ?

Answer 1

Molecules are made up by the combination of atoms in different proportions. Hence, atomicity is defined as the total number of atoms of different elements that are present in a molecule. Molecules can be monatomic, diatomic, triatomic and polyatomic based on the total number of atoms present in them.

Complete answer:
We know that matter is anything in space which has mass and volume (which means it occupies space). Matter is made up of smaller units called molecules and atoms. Molecules are made up of the atoms of different elements combined in different proportions.
So, we can define atomicity as the total number of atoms that make up a molecule or in other way atomicity is the total number of atoms that are present in a molecule.
If there is only one atom then we can say that it is monatomic and if there are two atoms in a molecule, then we can say that it is diatomic. Hence, polyatomic is said when a molecule contains three or more electrons in it.
Now, if we calculate the atomicity of ${P_4}{O_{10}}$ :
We can see that there are four atoms of phosphorus and ten atoms of oxygen in the molecule and hence the atomicity can be calculated as:
$Atomicity = 4 + 10$
$Atomicity = 14$
Hence, the atomicity of ${P_4}{O_{10}}$ is $14.$

Note:
We should not get confused between the terms atomicity and valency. Atomicity is defined as the total number of atoms of different elements that are present in a molecule while the valency of an atom is described as the number of electrons present in the outermost shell of the atom that it can donate to gain noble gas configuration.