Question

2. An element is a mixture of two isotopes. One isotope has an atomic mass of 34.969 amu and an

abundance of 64.88%. The other isotope has an atomic mass 36.966 amu. Create a data table for this
element like the one shown in #1. Calculate the average atomic mass of the element, and then use your
periodic table to identify the element.

Answer 1

0.3567

Step-by-step explanation:

Answer 2

Answer: The average atomic mass of an element is 35.67 amu and the unknown element will be chlorine.

Step-by-step explanation:

Mass of isotope 1 = 34.969 amu

% abundance of isotope 1 = 64.88% =
`(64.88)/(100)=0.6488`

Mass of isotope 2 = 36.966 amu

% abundance of isotope 2 = (100-64.88)% =
`(100-64.88)/(100)=0.3512`

Formula used for average atomic mass of an element :

`\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}* {{\text { fractional abundance}})`

`A=\sum[34.969* 0.6488)+(36.966 * 0.3512]]`

`A=35.67amu`

Therefore, the average atomic mass of an element is 35.67 amu and the unknown element will be chlorine.