What is the average atomic mass of lithium?

The average atomic mass of lithium can be calculated based on the natural abundance of its isotopes and their respective atomic masses.

Lithium has two stable isotopes: lithium-6 and lithium-7. The percentage abundance of these isotopes in naturally occurring lithium is approximately 7.5% for lithium-6 and 92.5% for lithium-7.

The atomic masses of lithium-6 and lithium-7 are approximately 6.0151223 atomic mass units (u) and 7.0160040 atomic mass units (u), respectively.

To calculate the average atomic mass of lithium, we use the following formula:

Average Atomic Mass = (Abundance of isotope 1 * Atomic mass of isotope 1) + (Abundance of isotope 2 * Atomic mass of isotope 2)

Average Atomic Mass of lithium = (0.075 * 6.0151223) + (0.925 * 7.0160040)
Average Atomic Mass of lithium ≈ 6.941 atomic mass units (u)

Therefore, the average atomic mass of lithium is approximately 6.941 atomic mass units.