Question

It is well known that the element magnesium has three naturally occurring isotopes. Mg-24 represents 79.0% of all magnesium atoms, Mg-25 accounts for 10.0%, and Mg-26 is the remaining 11.0%. If you have 226. atoms of magnesium, how many should be Mg-24?

Answer 1

Multiply the number of atoms by the % of Mg-24 and round to the closest integer.

226 * 79.0% = 178.54 = 179

Answer 2

Answer : The number of Mg-24 should be, 178.54

Solution :

As we are given the 79.0% of all magnesium atoms of Mg-24 and the number of magnesium atoms is 226. Now we have to calculate the number of Mg-24.

$\text{Number of Mg-24}=\frac{79.0}{100}\times \text{Number of magnesium atom}$

$\text{Number of Mg-24}=\frac{79.0}{100}\times 226=178.54$

Therefore, the number of Mg-24 should be, 178.54