Respuesta :
Answer:
b. K
Explanation:
The formula for the calculation of the average atomic mass is:
[tex]Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})+(\frac {\%\ of\ the\ third\ isotope}{100}\times {Mass\ of\ the\ third\ isotope})[/tex]
Given that:
For first isotope:
% = 93.08 %
Mass = 38.9637 amu
For second isotope:
% = 0.012 %
Mass = 39.9640 amu
For third isotope:
% = 6.91 %
Mass = 40.9618 amu
Thus,
[tex]Average\ atomic\ mass=\frac{93.08}{100}\times {38.9637}+\frac{0.012}{100}\times {39.9640}+\frac{6.91}{100}\times {40.9618}=36.26741196+0.00479568+2.83046038=39.1027\ amu[/tex]
Average atomic mass = 39.1027 amu
This mass corresponds to b. K Potassium.
Answer: The unknown element is potassium.
Explanation:
Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:
[tex]\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i[/tex] .....(1)
- For isotope 1:
Mass of isotope 1 = 38.9637 amu
Percentage abundance of isotope 1 = 93.08 %
Fractional abundance of isotope 1 = 0.9308
- For isotope 2:
Mass of isotope 2 = 39.9640 amu
Percentage abundance of isotope 2 = 0.012 %
Fractional abundance of isotope 2 = 0.00012
- For isotope 3:
Mass of isotope 3 = 40.9618 amu
Percentage abundance of isotope 3 = 6.91 %
Fractional abundance of isotope 3 = 0.0691
Putting values in equation 1, we get:
[tex]\text{Average atomic mass of Z}=[(38.9637\times 0.9308)+(39.9640\times 0.00012)+(40.9618\times 0.0691)][/tex]
[tex]\text{Average atomic mass of Z}=38.85amu[/tex]
For the given options:
Option a: Average atomic mass of Sulfur = 32.065 amu
Option b: Average atomic mass of Potassium = 39.09 amu
Option c: Average atomic mass of Chlorine = 35.45 amu
Option d: Average atomic mass of Calcium = 40.078 amu
Option e: Average atomic mass of Argon = 39.94 amu
As, the average atomic mass of unknown element is near to the average atomic mass of potassium. So, the unknown element is potassium.
Hence, the unknown element is potassium.
