Question

Oxygen occurs in nature as a mixture of isotopes $16O,^{17}Oand^{18}O$having atomic masses of $15.995$u $16.999$ u and $17.999$U and relative abundance of $99.763\%,0.037\% and0.200\%$ respectively.

What is the average atomic mass of oxygen?

• A. $15.999u$
• B. $16.999u$
• C. $17.999u$
• D. $18.999u$

Answer 1

Answer: (A)

$15.999u$

Answer 2

(1) : Atomic mass of oxygen

$= \frac{(99.763 \times 15.995) + (0.037 \times 16.999) + (0.200 \times 17.999)}{100}$

= $15.999u$