Question

What is the average mass of an element if it has two isotopes, one of mass 6.015 u with 8.24 % and other of mass 7.016 u with 91.26% respectively?

Options

• 7.156 u

• 7.551 u

• 6.515 u

• 6.899 u

Answer 1

6.899 u

Explanation:

Average isotopic mass = `8.24/100 xx 6.015 + 91.26/100 xx 7.016`

= 0.496 + 6.403

= 6.899 u