Answer
Weighted-average atomic mass of magnesium is approximately 24.309 u.
Work Step by Step
Taking into account the mass and abundance of each of its isotopes. We can use the following formula:
weighted-average atomic mass = (mass1 x abundance1) + (mass2 x abundance2) + (mass3 x abundance3) + ...
where mass1, mass2, mass3, etc. are the masses of each isotope, and abundance1, abundance2, abundance3, etc. are their respective abundances.
Using the given data for magnesium, we can plug in the values and calculate:
weighted-average atomic mass = (23.985042 u x 0.7899) + (24.985837 u x 0.1000) + (25.982593 u x 0.1101)
= 18.949 u + 2.499 u + 2.861 u
= 24.309 u
Therefore, the weighted-average atomic mass of magnesium is approximately 24.309 u.
