Radioactivity & Half Life Review

Front

What is alpha decay?

Back

A type of radioactive decay in which an atomic nucleus emits an alpha particle (2 protons and 2 neutrons), resulting in a new element with a lower atomic number.

Front

What is the half-life of a radioactive isotope?

Back

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

Front

If 10 mg of iodine-131 is given to a patient, how much is left after 24 days if its half-life is 8 days?

Back

1.25 mg

Front

What is the remaining percentage of a parent isotope after 3 half-lives?

Back

12.5%.

Front

What type of nuclear reaction occurs in the sun?

Back

Fusion.

Front

What is a chain reaction in nuclear fission?

Back

A process where neutrons released from one fission event cause additional fission events in nearby nuclei.

Front

What is the equation for alpha decay of Astatine-209?

Back

\( _{85}^{209}At \rightarrow _{83}^{205}Bi + _{2}^{4}He \)

Front

What happens to the mass number during alpha decay?

Back

It decreases by 4.

Front

What happens to the atomic number during alpha decay?

Back

It decreases by 2.

Front

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

Back

It allows scientists to determine the age of materials by measuring the remaining amount of a radioactive isotope.