Question

Thallium consists of 29.5%TI-203 and 70.5%TI-205. What is the relative atomic mass of thallium

Answer 1

To determine the relative atomic mass of thallium, we multiply the molar mass of the isotopes to their corresponding relative abundance. The molecular percentages should sum up to 1. In this case, we multiply 203 by 0.295 and 205 by 0.705 and add the answers of the two. The final atomic mass is 204.41 g/mol.