Antimony has 2 naturally occurring isotopes. The mass of antimony-121 is 120.904 amu and the mass of antimony-123 is 122.904 amu. Using the average atomic mass from the periodic table, find the abundance of each isotope.
(Remember that the sum of the two abundances must be 100%. Show your work.)
Answer (3)
Wow, now this one is a hard one, took me quite a while to figure it out but here it is: 120.904 ( x ) + 122.904 ( 1 − x ) = 121.76 120.904 x − 122.904 x + 122.904 = 121.76 − 2 x + 122.904 = 121.76 − 2 x = − 1.144 x = .572 1 − .572 = .428 The abundances of the two isotopes is: Antimony-121 = 57.2% Antimony-123 = 42.8%
To find the abundance of each isotope of antimony , set up a system of equations using the average atomic mass. Solve the system of equations to find the abundances. Double-check the average atomic mass provided. ;
The abundance of antimony-121 is approximately 57.2%, while the abundance of antimony-123 is about 42.8%. This is determined using a weighted average of the isotopes' masses and the average atomic mass of antimony. The equation used allows us to solve for the fractional abundances of each isotope.
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