Task 1.1d

1. Bromine exists as two isotopes with mass numbers 81 and 79.  If there is 50% of each isotope in a sample what is the relative atomic mass of bromine?

2. Calculate the relative atomic mass of the following:
(a) gallium 60% Ga 69 and 40% Ga 71
(b) neon 90% Ne 20 and 10% Ne 22
(c) silver 50% Ag 107 and 50% Ag 109
(d) boron 20% B 10 and 80% B 11
(e) neon 90.92% Ne 20, 8.82% Ne 22 and 0.26% Ne 21.
(f) lead 52.3% Pb 208, 22.6% Pb 207, 23.6% Pb 206 and 1.5% Pb 204.