radioactivity and half-life

Front

What is radioactivity?

Back

Radioactivity is the process by which unstable atomic nuclei lose energy by emitting radiation.

Front

What is a half-life?

Back

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

Front

If you start with 100g of a radioactive substance, how much will remain after one half-life?

Back

50g

Front

How much of a radioactive substance remains after two half-lives if you start with 100g?

Back

25g

Front

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

Back

1/8

Front

What is the remaining percentage of a parent isotope after three half-lives?

Back

12.5%.

Front

What type of nuclear reaction occurs in the sun?

Back

Fusion.

Front

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

Back

It decreases as the substance decays.

Front

What is the relationship between half-life and the stability of an isotope?

Back

Isotopes with shorter half-lives are generally less stable than those with longer half-lives.

Front

What is the decay constant?

Back

The decay constant is a value that represents the probability of decay of a radioactive isotope per unit time.