On a mission to a newly discovered planet, an astronaut finds gallium abundances of 60.11 % for 69Ga and 39.89 % for 71Ga. What is the atomic mass of gallium for this location

69.79

Explanation:

According to this question, Gallium element (Ga) has two isotopes namely: 69Ga and 71Ga respectively.

- Isotope 69Ga contains a percent abundance of 60.11 %, the decimal abundance= 0.6011

- Isotope 71Ga contains a percent abundance of 39.89 %, the decimal abundance = 0.3989

Atomic mass of Ga = (mass of isotope 1 × decimal abundance) + (mass of isotope 2 × decimal abundance)

Atomic mass of Ga = (0.6011 × 69) + (0.3989 × 71)

Atomic mass of Ga = 41.4759 + 28.3219

Atomic mass of Ga = 69.797

Atomic mass of Gallium = 69.79

14 days is the half-life of phosphorus-32