Question

#5 chemistry a schoology 2025
half - life is the amount of mass it takes for half of the radioactive nuclei in a sample to decay.
after one half - life, 50% of the original will remain.
after two half - lives, 25% of the original will remain.
after three half - lives, 12.5% of the original will remain.
possible points: 5

Explanation:

Step1: Define half - life concept

Half - life is the time for half of radioactive nuclei to decay.

Step2: Calculate remaining amount after one half - life

If we start with 100% of the original amount, after one half - life, the remaining amount is $100\%\times\frac{1}{2}=50\%$.

Step3: Calculate remaining amount after two half - lives

After two half - lives, the remaining amount is $50\%\times\frac{1}{2}=25\%$.

Step4: Calculate remaining amount after three half - lives

After three half - lives, the remaining amount is $25\%\times\frac{1}{2}=12.5\%$.

Answer:

After one half - life, 50% of the original will remain. After two half - lives, 25% of the original will remain. After three half - lives, 12.5% of the original will remain.