If Gallium-68 has a half-life of 68.3 minutes, how much of a 115 mg sample is left after 6 half-lives?
5 mg
1.8 mg
0.6 mg
none of the above

Use the periodic table to answer the following questions. what is the predicted order of first ionization energies from highest to lowest for beryllium, calcium, magnesium, and strontium? o be > ca > mg > sr o be > mg > ca > sr o ca > sr> be > mg o sr > ca > mg > be done