Question

How do you calculate atoms of an element?

Answer 1

Hint: If we know the mass of the substance or if we weight the substance and obtain the weight for solid phase substance. Find the number of moles of substance for the given quantity and from number of moles calculate the number of atoms.

Complete answer:
 So in the question it is asked how we could calculate the atoms of an element. We know that atoms are the basic unit of matter. We are dealing with atoms, matter, and atomic structure from the lower chemistry classes. Now we are going to discuss is about to find the number of atoms of an element for that also we should have some basic idea about what is mass of a substance and how it is related to a mole of a substance and how we can find number of atoms if we have number of moles of the substance.
So when we weigh a substance we will get the weight of the substance, so the weight we got is the mass of that substance we have taken. Now we do not know how much moles are there, or how many atoms are present in them.
We always love to reduce the calculation and always express quantity with less digits possible. Hence we generally refer to the quantity of a substance in moles. One mole of any substance will have Avogadro number of atoms, i.e. $6.022\times {{10}^{23}}$Atoms.
So first find the number of moles of the substance, when the weight of the substance is given.
To calculate the number of moles, divide the given mass of substance with its molecular mass.
$No.\,of\,moles=\dfrac{Given\,mass}{Molecular\,mass}$
Now we get the number of moles of the substance, multiply the answer with the Avogadro number and we will get the number of atoms in the element for the given weight.
$No.\,of\,atoms=No.\,of\,moles\times {{N}_{A}}$
$No.\,of\,atoms=No.\,of\,moles\times 6.022\times {{10}^{23}}$

Note:
We could find the mass number of the element i.e. the atomic mass of the substance with the aid of a periodic table.1 mole of any element will have the same number of atoms only, we used the concept of mole since the given mass of the substance will contain a large number of atoms. And if we calculate in terms of atoms it will make the calculations tougher.