## Chemistry: Molecular Approach (4th Edition)

Natural abundance of $\text{Li-7}$ is more than the natural abundance of $\text{Li-6}$, which means that $\text{Li-7}$ is more abundant than the $\text{Li-6}$ isotope. Hence, the atomic mass of lithium will be more than the atomic mass of $\text{Li-7}$, and the correct answer is option (c). The atomic mass of lithium cannot be close to $6.00\text{amu}$ or $6.50\text{amu}$, because the relative abundance of $\text{Li-7}$ is more as compared to $\text{Li-6}$. Thus, the atomic mass of lithium will be closer to the atomic mass of $\text{Li-7}$. Hence, options (a) and (b) are incorrect.