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

CHEMISTRY · Single correct · A Level · Chemistry · Atomic structure · Atomic structure

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\%

(b)

31\%

(c)

54\%

(d)

63\%