Magnesium has three naturally occurring isotopes: 24 Mg (23.985 amu) with 78.99% abundance, 25 Mg (24.986 amu) with 10.00% abundance, and a third with 11.01% abundance. Look up the atomic mass of magnesium, and then calculate the mass of the third isotope.
23.985(0.7899) + 24.986(0.1000) + (x)(0.1101) = mass you look up.
Solve for x.
Check my thinking.
I don't know what 2.311023x stands for but it isn't the mass of the third isotope.
To calculate the mass of the third isotope of magnesium, we need to use the information provided about the abundances and mass of the other two isotopes.
Firstly, we need to determine the atomic mass of magnesium. This can be looked up on the periodic table, where the atomic mass is usually given as an average value due to the presence of different isotopes. The atomic mass of magnesium is approximately 24.31 amu.
Now, let's calculate the mass of the third isotope. We know that the average atomic mass takes into account the abundances of each isotope. Given that the first isotope (24Mg) has an abundance of 78.99% and the second isotope (25Mg) has an abundance of 10.00%, we can determine the abundance of the third isotope by subtracting the total abundances of the first two isotopes from 100%:
Abundance of third isotope = 100% - (78.99% + 10.00%) = 11.01%
Next, we can set up an equation to solve for the mass of the third isotope, denoted as x:
(78.99%/100) * 24.985 amu + (10.00%/100) * 25.986 amu + (11.01%/100) * x = 24.31 amu
Simplifying the equation:
0.7899 * 24.985 + 0.1000 * 25.986 + 0.1101 * x = 24.31
19.7309 + 2.5986 + 0.1101 * x = 24.31
22.3295 + 0.1101 * x = 24.31
0.1101 * x = 1.9805
x ≈ 17.97 amu
Therefore, the mass of the third isotope of magnesium is approximately 17.97 amu.