After 1 half-life, what percentage of the original number of parent atoms is left?  _______ (a number)

Which one of the following decreases over time?Group of answer choicesthe decay ratethe number of parent atomsthe number of daughter atomsthe length of a half-life

How many half-lives must elapse until 78.0% of a radioactive sample of atoms has decayed? (Note that there is no unit for this answer.)

Which one of the following is dependent on temperature?Group of answer choicesclosurethe half-lifethe radioactive decay ratethe number of daughter atomsthe number of parent atoms

A hormone has a half-life of 20 minutes. After an hour, __________Blank percent of the original number of molecules remains.Multiple Choice012.52550

The half-life of cesium-137 is 30 years. How many percent of the atoms of this isotope decay in 240 years?