Answer to Question #69167 in Chemistry for Sabrine Nibamwe

Question

The figure below shows the mass spectrum of lead as obtained from the mass spectrometer:

a) Calculate the relative atomic mass of lead.
b) State and explain the number of isotopes in natural lead.

Answer 1

The relative atomic mass is worked out using the following formula, illustrated for two isotopes, where the abundances are given in percentage values.
A_r=((mass1 x abundance 1)+(mass2 x abundance2)+⋯)/100
Natural lead consists of four stable isotopes with mass numbers of 204, 206, 207, and 208, and traces of five short-lived radioisotopes.