At what point is the half-life of a radioactive isotope reached? A. When half the parent nuclei in a sample have become daughter nuclei
B. When all the daughter nuclei in a sample have become parent nuclei
C. When half the daughter nuclei in a sample have become parent nuclei
D. When all the parent nuclei in a sample have become daughter nuclei

A. When half the parent nuclei in a sample have become daughter nuclei

Explanation:

The point at which the half-life is reached is when half of the parent nuclei in a sample have become daughter nuclei.

Every radioactive atom starts with the parent. When they disintegrate they given the daughter nuclides.

The half - life is the time taken for half of the radioactive nuclei to disintegrate.

The shorter the half - life, the faster the decay process.

your answer is, orbit around the nucleus