Question

question 4. magnesium consists of three isotopes with masses of 23.98 amu (78.6%), 24.98 amu (10.1%), and 25.98 amu (11.3%). calculate the atomic mass of mg.

Explanation:

Step1: Convert percentages to decimals

$78.6\% = 0.786$, $10.1\%=0.101$, $11.3\% = 0.113$

Step2: Multiply each isotope mass by its abundance

For the first isotope: $23.98\times0.786 = 18.84828$
For the second isotope: $24.98\times0.101=2.52298$
For the third isotope: $25.98\times0.113 = 2.93574$

Step3: Sum up the results

$18.84828+2.52298 + 2.93574=24.307$

Answer:

$24.31$ amu (rounded to two - decimal places)