Question

I WILL GIVE YOU 10 POINTS!!!

A newly discovered element, Z, has two naturally occurring isotopes. 90.3 percent of the sample is an isotope with a mass of 267.8 u, and 9.7 percent of the sample is an isotope with a mass of 270.9 u. What is the weighted average atomic mass for this element?
268.1 u
269.0 u
269.4 u
270.6 u

Answer 1

267.8 * 0.903) + (270.9 * 0.097) = 268.1 u

Answer 2

the answer is 268.1 u....