calculate the average atomic mass for an unidentified element given the following; isotope % abundance…

calculate the average atomic mass for an unidentified element given the following; isotope % abundance relative mass mass contribution x-24 78.994 23.985041700 amu (__1__)(23.985041700 amu) = __2__ amu x-25 10.001 24.98583692 amu (__3__)(24.98583692 amu) = __4__ amu x-26 11.013 25.982592929 amu (__5__)(25.982592929 amu)= __6__ amu __7__ amu from the periodic table the element must be __8__ a. 11.013 b. 24.307 c. 2430.7 d. 0.11013 e. 0.10001 f. 0.78994 g. 18.946744 h. 2.861463 i. 2.498834 j. ne k. na l. mg m. al n. si
Answer
Explanation:
Step1: Convert X - 24 % abundance to decimal
To use the percentage abundance in calculations, we divide by 100. So for X - 24 with 78.994% abundance, the decimal - form is $\frac{78.994}{100}=0.78994$. So, 1 = F.
Step2: Calculate X - 24 mass contribution
Multiply the decimal - form of abundance by the relative mass. $(0.78994)(23.985041700\ amu)\approx18.946744\ amu$. So, 2 = G.
Step3: Convert X - 25 % abundance to decimal
Divide the percentage abundance of X - 25 (10.001%) by 100. $\frac{10.001}{100}=0.10001$. So, 3 = E.
Step4: Calculate X - 25 mass contribution
Multiply the decimal - form of abundance by the relative mass. $(0.10001)(24.98583692\ amu)\approx2.498834\ amu$. So, 4 = I.
Step5: Convert X - 26 % abundance to decimal
Divide the percentage abundance of X - 26 (11.013%) by 100. $\frac{11.013}{100}=0.11013$. So, 5 = D.
Step6: Calculate X - 26 mass contribution
Multiply the decimal - form of abundance by the relative mass. $(0.11013)(25.982592929\ amu)\approx2.861463\ amu$. So, 6 = H.
Step7: Calculate average atomic mass
Add up the mass contributions of all isotopes: $18.946744 + 2.498834+2.861463 = 24.307041\ amu\approx24.307\ amu$. So, 7 = B.
Step8: Identify the element
Looking at the periodic table, an element with an average atomic mass of approximately 24.307 amu is Magnesium (Mg). So, 8 = L.
Answer:
- F. 0.78994
- G. 18.946744
- E. 0.10001
- I. 2.498834
- D. 0.11013
- H. 2.861463
- B. 24.307
- L. Mg