Question

1. naturally occurring europium (eu) consists of two isotopes was a mass of 151 and 153. europium - 151 has an abundance of 48.03% and europium - 153 has an abundance of 51.97%. what is the atomic mass of europium?

Explanation:

Step1: Convert percentages to decimals

$48.03\% = 0.4803$, $51.97\%=0.5197$

Step2: Calculate weighted - mass of Eu - 151

$151\times0.4803 = 72.5253$

Step3: Calculate weighted - mass of Eu - 153

$153\times0.5197=79.5141$

Step4: Calculate atomic mass of europium

$72.5253 + 79.5141=152.0394\approx152.04$

Answer:

$152.04$