Question

Magnesium occurs naturally in only three isotopes. ^24 Mg has an isotopic mass of 23.9850 amu and an abundance of 78.99%. ^25 Mg has an isotopic mass of 24.9858 amu and an abundance of 10.00%. Find the mass number of the last isotope of magnesium.

Can someone please explain how to solve this? *done mine the notes*

Answer 1

Answer:

25,98 amu and 11.01% abundance

Explanation:

1. Find the missing abundance

100 - 78.99 - 10 = 11.01 %

2. Using each mass and abundance and the periodic table for the Mg amu

And let Isotope = Mg

23.9850(78.99%) + 24.9858(10%) + Mg(11.01%) = 24.305 (100%)

Solve for Mg

Mg = 25,98