Problem: Naturally occurring magnesium has an atomic mass of 24.312 and consists of three isotopes. The major isotope is 24Mg, natural abundance 78.99%, relative atomic mass 23.98504. The next most abundant isotope is 26Mg, relative atomic mass 25.98259. The third isotope is 25Mg whose natural abundance is in the ratio of 0.9083 to that of 26Mg.Find the relative atomic mass of 25Mg.

🤓 Based on our data, we think this question is relevant for Professor Perry's class at NSU.

FREE Expert Solution

We’re being asked to calculate the relative atomic mass of magnesium-25 (Mg-25). We can use the following equation:


Atomic Mass = [mass × f.a.]isotope 1 + [mass × f.a.]isotope 2....



where atomic mass = average atomic mass of the element and f.a. = fractional abundance of the isotope. To get f.a., we simply need to divide the given percent abundance by 100.


View Complete Written Solution
Problem Details

Naturally occurring magnesium has an atomic mass of 24.312 and consists of three isotopes. The major isotope is 24Mg, natural abundance 78.99%, relative atomic mass 23.98504. The next most abundant isotope is 26Mg, relative atomic mass 25.98259. The third isotope is 25Mg whose natural abundance is in the ratio of 0.9083 to that of 26Mg.

Find the relative atomic mass of 25Mg.

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Isotopes concept. You can view video lessons to learn Isotopes. Or if you need more Isotopes practice, you can also practice Isotopes practice problems.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Perry's class at NSU.