Question

Compute the mass (in grams) of a single iodine atom if the relative atomic mass of iodine is 126.90447 on the accepted scale of atomic masses (based on 12 as the relative atomic mass of 12 C)?

Short answer

The mass of 1 atom of iodine is $2.1072982\times {10}^{-22}g$.

Step-by-step solution

Relative mass of iodine

The atomic mass of an element is equal to the mass of the number of atoms of the element.

N_A = Avogadro number = $6.023\times {10}^{23}$.

Relative mass of iodine atom =$6.023\times {10}^{23}$

It means atoms of iodine = 126.90447 g.

Mass of one atom of iodine

The formula for evaluating the mass of 1 atom of iodine is

$$\begin{gathered} \mathbf{The}\mathbf{}\mathbf{mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{one}\mathbf{}\mathbf{atom}\mathbf{}\mathbf{of}\mathbf{}\mathbf{iodine}\mathbf{}\mathbf{}\mathbf{=}\frac{\mathbf{Relative}\mathbf{}\mathbf{mass}}{\mathbf{Number}\mathbf{}\mathbf{of}\mathbf{}\mathbf{atoms}} \\ =\frac{126.90447g}{6.023\times {10}^{23}} \\ =2.1072982\times {10}^{-22}g \end{gathered}$$

Thus, the mass of 1 atom of iodine is $2.1072982\times {10}^{-22}g$.