Question

The elements below show the atomic number, element

symbol, average atomic mass, and element name. Which
of the following best explains how average atomic mass is
found?

Answer 1

Using the percentage method . Taking a small sample and measuring the percentage of each isotope then calculating average atomic mass.

Step-by-step explanation:

Average atomic mass can be determine by percentage method.

Consider the following example:

Abundance of C¹² = 98.89%

Abundance of C¹³ = 1.11%

Atomic mass of C¹² = 12.000 amu

Atomic mass of C¹³ = 13.003 amu

Average atomic mass = ?

Solution:

Average atomic mass of carbon = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100

Average atomic mass of carbon = (12.000×98.89)+(13.003×1.11) /100

Average atomic mass of carbon= 1186.68 + 14.43333 / 100

Average atomic mass of carbon = 1201.11333 / 100

Average atomic mass of carbon = 12.01 amu