A newly discovered element, X, has two naturally occurring isotopes. 93.5 percent of the sample is an isotope with a mass of 268.9 u, and 6.5 percent of the sample is an isotope with a mass of 269.9 u. What is the weighted average atomic mass for this element? (2 points)
Question 5 options:

1) 268.5 u
2) 269.0 u
3) 269.4 u
4) 269.8 u

Question

A newly discovered element, X, has two naturally occurring isotopes. 93.5 percent of the sample is an isotope with a mass of 268.9 u, and 6.5 percent of the sample is an isotope with a mass of 269.9 u. What is the weighted average atomic mass for this element? (2 points)
Question 5 options:

 1) 268.5 u 
 2) 269.0 u 
 3) 269.4 u 
 4) 269.8 u

ipwnbunnies · Answer

The weighted average atomic mass for this element will be the sum of the fractions from each isotope.
$$avg = (268.9)(0.935) + (269.9)(0.065)$$

juanpablojr · Answer

yessssss!