A sample of gallium has only two isotopes. Out of every 10 atoms in the sample, 6 contain 38 neutrons and 4 contain 40 neutrons. Calculate the relative atomic mass, $A_r$, for the gallium in the sample.
- A69.7
- B69.8
- C70.0
- D70.2
Chemistry 9701 · AS & A Level · 1.1
A sample of gallium has only two isotopes. Out of every 10 atoms in the sample, 6 contain 38 neutrons and 4 contain 40 neutrons. Calculate the relative atomic mass, $A_r$, for the gallium in the sample.