Half-Lives

The diagram shows 32 atoms.

16 of the Red are parent isotopes

16 of the Green are daughter isotopes

How many half-lives have occurred?

• 0

• 1

• 2

• 3

Tags

NGSS.HS-PS1-8

What is the Half life of this isotope?

• 5 seconds

• 10 seconds

• 15 seconds

• 20 seconds

Tags

NGSS.HS-PS1-8

What is the Half Life of this isotope?

• 3 days

• 5 days

• 8 days

• 10 days

Tags

NGSS.HS-PS1-8

The % of the parent isotope remaining after 2 Half Lives.

• 50%

• 25%

• 12.5%

• 6.25%

Tags

NGSS.HS-PS1-8

After one half life, a sample will begin to have more of the parent isotope than the daughter isotope.

• TRUE

• FALSE

Tags

NGSS.HS-PS1-8

A sample will lose half of the parent isotope after 1 half life.

• TRUE

• FALSE

Tags

NGSS.HS-PS1-8

Which is used in radioactive dating?

• Carbon-14

• Index fossils

• Hydrochloric acid

• Law of superposition

What is the half-life of iodine-131?

• 32 days

• 8 days

• 16 days

• 24 days

Tags

NGSS.HS-PS1-8

An isotope has a half life of 20 years. If it starts with a sample of 100g, how much of it will be left after 80 years?

• 25 grams

• 50 grams

• 6.25 grams

• 12 grams

After 2 half lives have passed, what percent of the parent isotope is left?

• 25%

• 50%

• 75%

• 100%

Tags

NGSS.HS-PS1-8