Lithium Forms Compounds Which Are Used in Dry Cells and Storage

Multiple Choice

Lithium forms compounds which are used in dry cells and storage batteries and in high-temperature lubricants. It has two naturally occurring isotopes, ⁶Li (isotopic mass = 6.015121 amu) and ⁷Li (isotopic mass = 7.016003 amu) . Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6?

A) 92.50%
B) 86.66%
C) 46.16%
D) 7.503%
E) 6.080%