isotopes and average atomic mass\n1) which of the following are not an isotope of carbon?\nthe average…
isotopes and average atomic mass\n1) which of the following are not an isotope of carbon?\nthe average atomic mass formula is: ((mass#1xpercent abundance) + (mass#2xpercent abundance) + ....)/100\n2) calculate the average atomic mass of the following: show all work!!!\nisotope mass (amu) percent abundance\nmagnesium - 24 23.985 78.70%\nmagnesium - 25 24.986 10.03%\nmagnesium - 26 25.983 11.17%\n3) calculate the average atomic mass of the following: show all work!!!\nisotope mass (amu) percent abundance\nlithium - 6 6.015 7.50%\nlithium - 7 7.016 92.50%
Answer
Explanation:
Step1: Recall isotope definition
Isotopes of an element have the same number of protons but different numbers of neutrons. Carbon has 6 protons. Without seeing the details of the diagrams (A, B, C), we can't answer the first part.
Step2: Calculate average atomic mass of magnesium
Use the formula $\frac{(mass#1\times percent\ abundance)+(mass#2\times percent\ abundance)+(mass#3\times percent\ abundance)}{100}$. [ \begin{align*} &=\frac{(23.985\times78.70)+(24.986\times10.03)+(25.983\times11.17)}{100}\ &=\frac{(23.985\times0.787)+(24.986\times0.1003)+(25.983\times0.1117)}{1}\ &=\frac{18.876295 + 2.5060958+2.9023011}{1}\ &=\frac{24.2846919}{1}\ &\approx 24.31 \end{align*} ]
Step3: Calculate average atomic mass of lithium
[ \begin{align*} &=\frac{(6.015\times7.50)+(7.016\times92.50)}{100}\ &=\frac{(6.015\times0.075)+(7.016\times0.925)}{1}\ &=\frac{0.451125+6.4898}{1}\ &=\frac{6.940925}{1}\ &\approx 6.94 \end{align*} ]
Answer:
- Can't answer without diagram details
- Approximately 24.31 amu
- Approximately 6.94 amu