Geologic Time Goal E Flashcard

Front

What is half-life?

Back

The length of time required for half of the radioactive atoms in a sample to decay.

Front

What happens to the amount of parent isotope after one half-life?

Back

It reduces to half of its original amount.

Front

If you start with 1000 atoms of a parent isotope, how many will remain after 2 half-lives?

Back

250 atoms.

Front

What is the parent element in radioactive decay?

Back

The original element that undergoes radioactive decay.

Front

How many half-lives are needed for a sample to reduce to 25% of its original amount?

Back

2 half-lives.

Front

If the half-life of an isotope is 10 seconds, how much time will it take for a sample to decay to 125 atoms from 1000?

Back

30 seconds.

Front

What is the relationship between half-life and radioactive decay?

Back

Half-life is a measure of the rate at which a radioactive isotope decays.

Front

What is a daughter element?

Back

The product of the decay of a parent element.

Front

If a sample has 75% of the parent isotope remaining, how many half-lives have passed?

Back

1 half-life.

Front

What is the significance of knowing the half-life of an isotope?

Back

It helps in determining the age of rocks and fossils through radiometric dating.