Final answer:
The average atomic mass of magnesium is calculated by multiplying each isotope's atomic mass by its relative abundance and summing the results, which gives approximately 24.31 amu.
Step-by-step explanation:
To calculate the average atomic mass of magnesium, we'll use the atomic masses and relative abundances of its isotopes. The formula for average atomic mass is:
M_{avg} = (Mass_{isotope1} \times Abundance_{isotope1}) + (Mass_{isotope2} \times Abundance_{isotope2}) + ... + (Mass_{isotopeN} \times Abundance_{isotopeN})
Substituting the given values into the formula, we get:
M_{avg} = (23.985 amu \times 0.78999) + (24.986 amu \times 0.10000) + (25.982 amu \times 0.1101)
M_{avg} = (18.9501515 amu) + (2.4986 amu) + (2.859962 amu)
M_{avg} = 24.3087135 amu
So, the average atomic mass of magnesium is approximately 24.31 amu.