Chapter 2 - Exercises - Page 83: 134

C

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.