Use the decay curve. What is the half-life of the isotope?

Use the remaining-mass curve. How much isotope remains at 6 days?

Use the activity curve. At what time is one quarter of the original activity left?

Use the remaining-mass curve. What half-life is shown by the graph?

Use the activity curve. What activity remains at 30 seconds?

Use the remaining-mass curve. When is one eighth of the original mass left?

Use the activity curve. What half-life is shown?

Use the remaining-mass curve. How much isotope remains after 45 minutes?

Use the activity curve. At what time is one eighth of the original activity left?

Use the remaining-mass curve. What is the half-life of the isotope?

Use the activity curve. What activity remains at 16 minutes?

Use the remaining-mass curve. When does the sample first reach 6 g?

Radium-226 alpha-decays: (226,88)Ra -> ? + (4,2)He. What daughter nucleus conserves mass number and charge?

Carbon-14 beta-minus decays: (14,6)C -> ? + (0,-1)e. Which daughter nucleus balances the equation?

Cobalt-60 beta-minus decays: (60,27)Co -> ? + (0,-1)e. What daughter nucleus is produced?

An excited nickel nucleus drops to its ground state: (60,28)Ni* -> (60,28)Ni + ?. What emission belongs in the equation?

Uranium-238 alpha-decays: (238,92)U -> ? + (4,2)He. Which daughter nucleus balances the equation?

Thorium-232 alpha-decays: (232,90)Th -> ? + (4,2)He. What is the daughter nucleus?

Plutonium-239 alpha-decays: (239,94)Pu -> ? + (4,2)He. Which product conserves A and Z?

Bismuth-211 beta-minus decays: (211,83)Bi -> ? + (0,-1)e. What daughter nucleus is formed?

Polonium-210 alpha-decays: (210,84)Po -> ? + (4,2)He. Which daughter nucleus is correct?

Cesium-137 beta-minus decays: (137,55)Cs -> ? + (0,-1)e. Ignoring later gamma emission, what daughter nucleus balances this step?

A sample starts with 40.0 g of an isotope whose half-life is 12 years. How much remains after 36 years?

A source begins at 800 Bq and has a half-life of 5 minutes. What activity remains after 15 minutes?

An isotope sample starts at 64 g and has a half-life of 2 days. How much remains after 8 days?

A radioactive sample has an initial activity of 1200 Bq and a half-life of 3 hours. What activity remains after 6 hours?

A 10.0 g sample has a half-life of 7 years. How much of the isotope remains after 21 years?

A detector reads 96 Bq from a source with a half-life of 4 seconds. What activity remains after 16 seconds?

A sample starts with 256 g of a radioisotope. Its half-life is 10 minutes. How much remains after 30 minutes?

A source has activity 500 Bq and a half-life of 2 hours. What activity remains after 8 hours?

Which statement best describes radioactive decay?

Which radiation has charge +2e and is the least penetrating of alpha, beta, and gamma radiation?

Which radiation consists of fast-moving electrons, each with charge -1e, emitted from an unstable nucleus?

Which radiation has no electric charge and is a high-energy photon from the nucleus?

Rank alpha, beta, and gamma radiation from least penetrating to most penetrating.

A sheet of paper placed between a sealed source and a detector drops the reading almost to background. Which radiation is most likely being blocked?

Paper has little effect, but a few millimeters of aluminum blocks most of the radiation from a source. Which radiation is most likely?

What is Marie Curie correctly credited with in the study of radioactivity?

What did Rutherford's alpha-scattering work establish about the atom?

Which statement correctly compares fission, fusion, and the energy they can release?