Question

element x has three stable isotopes. x - 12 has 80% abundance. x - 13 has 15% abundance. x - 14 has 5% abundance. without calculating the average, which of the following average atomic masses is not even possible. (select all that apply!) 13.24 15.01 12.88 11.98

Explanation:

Step1: Analyze isotope abundances

The most abundant isotope is X - 12 with 80% abundance. The average atomic mass will be close to 12.

Step2: Consider range

Since the other isotopes are X - 13 (15% abundance) and X - 14 (5% abundance), the average atomic mass will be greater than 12 but less than 13 (because 80% of the contribution is from X - 12).

Answer:

15.01