Gallium has a weighted average atomic mass of 69.7 and two naturally occurring isotopes: gallium-69 and gallium-71. Gallium-69 has a relative abundance of 60.1% and a mass of 68.9. The relative abundance of gallium-71 is 39.9%. Based on this information, what is the mass of gallium-71?

Question

ipwnbunnies · Answer

So gallium-69 and gallium-71 are two isotopes that make up the atomic mass number you see on the Periodic Table.

ipwnbunnies · Answer

The two isotopes have a relative abundance, how much of it exists.
So. The atomic mass = relative mass of each isotope

ipwnbunnies · Answer

$$69.7 = (68.9)(0.601) + (x)(0.399)$$
Where 'x' is the atomic mass of Gallium-79.

anonymous · Answer

<3

ipwnbunnies · Answer

I convert the percentages to decimals.