Question

Magnesium has three naturally occurring isotopes with masses of 23.99 amuamu, 24.99 amuamu, and 25.98 amuamu and natural abundances of 78.99%%, 10.00%%, and 11.01%%, respectively. Calculate the atomic mass of magnesium.

Answer 1

Answer:

Relative atomic mass of magnesium is 24.3

Explanation:

The relative atomic mass (R. A. M) of an element which exhibits isotopy is the average mass of its various isotopes as they occur naturally in any quantity of the element.

To calculate the relative atomic mass, multiply the percentage value of each with its corresponding mass and add the values together.

R. A. M = ( 78.99/100 * 23.99) + (10/100 * 24.99) + (11.01/100 * 25.98)

R. A. M = 18.949701 + 2.499 + 2.860398

R. A. M = 24.30099

R. A. M = ~ 24.3

Answer 2

Answer:

24.309 g/mol

Explanation:

To get the atomic mass, all we have to do is calculate with the masses of the three isotope, the real quantity present, taking account of the percent and then, do a sum of these three values. Like a pondered media.

For the first isotope:

23.99 * (78.99/100) = 18.95 g/mol

For the second isotope:

24.99 * (10/100) = 2.499 g/mol

For the last isotope:

25.98 * (11.01/100) = 2.86 g/mol

Now, let's sum all three together

AW = 18.95 + 2.499 + 2.86

AW = 24.309 g/mol