Question

What is the relative atomic mass of an element

whose isotopic composition is 90% of 20x and 10% of 22x
​

Answer 1

20.2 amu.

Step-by-step explanation:

Let A represent isotope ²⁰X

Let B represent isotope ²²X

From the question given above, the following data were obtained:

For Isotope A (²⁰X):

Mass of A = 20

Abundance (A%) = 90%

For Isotope B (²²X):

Mass of B = 22

Abundance (A%) = 10%

Relative atomic mass (RAM) =?

The relative atomic mass (RAM) of the element can be obtained as follow:

RAM = [(Mass of A × A%)/100] + [(Mass of B × B%)/100]

RAM = [(20 × 90)/100] + [(22 × 10)/100]

RAM = 18 + 2.2

RAM = 20.2 amu

Thus, relative atomic mass (RAM) of the element is 20.2 amu