Question

Europium consists of $47.8$% Eu-$151$ and $52.2$% Eu-$153$. Calculate average atomic mass?

• A. $152.2$
• B. $152.1$
• C. $151.9$
• D. $152$

Answer 1

The correct option is D $152$

Average atomic mass is given by:

$M_{av}=\frac{151\times 0.478+153\times 0.522}{0.478+0.522}=152.044gm/mol$