Asample of phosphorus-32 has a half-life of 14.28 days. if 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample?

Which electron configuration represents the electrons in an atom of sodium in the ground state at stp

Carbon-14 undergoes radioactive decay in the reaction above. determine the type of radiation emitted in this reaction and describe what is happening to the nucleus during this reaction.

An unknown insoluble substance displaced the water shown. it's mass is indicated on the triple beam balance. mass = a. 694 b. 693.5 c. 693.0 d.693.8