Radioactive Decay

Front

What is Radioactive Decay?

Back

The process by which an unstable atomic nucleus loses energy by emitting radiation.

Front

What is a Half-life?

Back

The amount of time it takes for half the nuclei in a sample of the isotope to decay.

Front

If 25% of the original radioactive atoms remain, how many half-lives have passed?

Back

2 half-lives.

Front

What fraction of a radioactive substance remains after 3 half-lives?

Back

1/8.

Front

How do you calculate the remaining amount of a substance after a certain number of half-lives?

Back

Use the formula: Remaining Amount = Initial Amount * (1/2)^(number of half-lives).

Front

What is the remaining percentage of carbon-14 after 22,800 years?

Back

6.25%.

Front

If an isotope has a half-life of 10 minutes, how much remains after 1 hour?

Back

1/64 of the original mass.

Front

How long will it take for a 28-gram sample of radon-222 to decay to 3.5 grams if its half-life is 3.82 days?

Back

11.46 days.

Front

What happens to the mass of a radioactive substance over time?

Back

It decreases as the substance decays into other elements or isotopes.

Front

What is the significance of the half-life in radioactive decay?

Back

It helps determine the age of materials and the rate of decay of radioactive substances.