Radioactivity and Half-Life

How many half-lives does it take a radioactive substance to decay until only one-eighth (1/8) of the original substance remains.

• 2

• 3

• 6

• 8

Tags

NGSS.HS-PS1-8

Sodium-24 has a half-life of approximately 15 hours. If only one-eighth of the sodium-24 remains, about how much time has passed.

• 15 hours

• 30 hours

• 45 hours

• 60 hours

Tags

NGSS.HS-PS1-8

Cerium-143 is a radioactive isotope that decays to produce praseodymium-143. The half-life for cerium-143 is approximately 33 hours. If 6.25 g cerium-143 remains from a 100-g sample, which statement is true? Select all that apply.

• Cerium-143 decayed for 132 hours.

• Cerium-143 decayed for 166 hours.

• Two half-lives have passed.

• Three half-lives have passed.

• Four half-lives have passed.

Tags

NGSS.HS-PS1-8

The graph shows the radioactive decay of a bone that is found to contain 1/8 of the carbon-14 found in living animals today.

• 5,790 years

• 11,460 years

• 17,190 years

• 22,920 years

Tags

NGSS.HS-PS1-8

Which statement best describes what happens in a fission reaction?

• Light nuclei form into heavier nuclei.

• Heavy nuclei split into lighter nuclei.

• Energy is released, and less stable elements are formed.

• Energy is absorbed, and more stable elements are formed.

Tags

NGSS.HS-PS1-8

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

• Half-Life

• Radioactivity

• Nuclear Fission

• Nuclear Fusion

Tags

NGSS.HS-PS1-8

If the half-life of 100 grams of a radioactive isotope is 8 years, how many grams will remain in 32 years?

• 50g

• 6.25g

• 25g

• 12.5g

half-life of a 50.0 gram sample is 3 years... how much in 3 more years?

• 15.0g

• 12.5g

• 25.0g

• 50.0g

A beta particle is when...

• The atomic number decreases by 1

• The atomic number increases by 1

• The atomic number stays the same

• The atomic number turns to 0

Tags

NGSS.HS-PS1-8

What makes something radioactive?

• stable nucleus

• electromagnetic waves

• unstable nucleus

• light waves

Tags

NGSS.HS-PS1-8