Question

element x has three isotopes:

• x - 39: atomic mass = 38.96 amu, abundance = 93.26%
• x - 40: atomic mass = 39.96 amu, abundance = 0.01000%
• x - 41: atomic mass = 40.96 amu, abundance = 6.730%

the average atomic mass of element c is: amu

Explanation:

Step1: Convert percentages to decimals

$93.26\%=0.9326$, $0.01000\% = 0.0001$, $6.730\%=0.0673$

Step2: Multiply each isotope's mass by its abundance

For X - 39: $38.96\times0.9326=36.343096$
For X - 40: $39.96\times0.0001 = 0.003996$
For X - 41: $40.96\times0.0673=2.756608$

Step3: Sum up the results

$36.343096+0.003996 + 2.756608=39.1037$

Answer:

$39.10$ amu