Chemistry

Problem

An element R has three naturally occurring isotopes with the following masses: • R-63:

62.93\,\text{amu}

• R-64:

63.93\,\text{amu}

• R-65:

64.94\,\text{amu}

Spectroscopic analysis shows that the percent abundance of R-64 is twice that of R-65. The average atomic mass of R is

63.55\,\text{amu}

. What is the percent abundance of isotope R-63? a)

59\%

31\%

54\%

63\%