Calculate the atomic mass of element "X," if it has 2 naturally occurring isotopes with the following masses and natural abundances. X-107 106.90509 amu 51.84%
X-109 108.90476 amu 48.46%
A) 107.90 amu
B) 108.00 amu
C) 107.79 amu
D) 108.32 amu
E) 108.19 amu

Question

Quizplus · Accepted Answer

To calculate the atomic mass of an element with multiple isotopes, the masses of the isotopes are multiplied by their respective percentages, then added together.

((106.90509 amu) x 0.5184) + ((108.90476 amu) x 0.4846) = 55.43211984 amu + 52.73934296 amu
= 108.1714628 amu

Rounding to two decimal places, the correct answer is E) 108.19 amu.

Calculate the Atomic Mass of Element "X," If It Has