Radioactive decay

Radioactive decay is where a parent isotope (carbon14, uranium238, potassium40 or Rubidium87) is UNSTABLE and changes to a STABLE daughter element. This decay is predictable and constant. the decay is called half-life and that is the time it takes the parent isotope to change into the daughter. For example, carbon14 takes 5,700 years for half of a sample to change to nitrogen14. So if you started with 100 grams of carbon14 then after 5700 years you would have 50 grams of carbon14 and 50 grams of nitrogen14. Add another 5,700 years or 11,400 years in total, then you have 25 grams of carbon 14 and 75 grams of nitrogen14. What does U238 decay into? ESRT's!!!!!!

• Pb206

• U238

• Sr87

Tags

NGSS.HS-PS1-8

Which element is useful for determining the age of the EARTH? hint hint the unstable element needs to have a half life SIMILAR to the age of the earth!!!

• Carbon 14

• Potassium 40

• Uranium 238

Match the following

• Ar40

• Rb87

• N14

• potassium 40

• Sr87

• C14

• Pb206

• U238

Tags

NGSS.HS-PS1-8

Which radioactive isotope is used to absolute date a mammoth or condor fossil which is relatively young??

• Potassium 40

• Carbon 14

• Rubidium 87

• Uranium 238

Tags

NGSS.HS-PS1-8

Which radioactive isotope is used to date organic fossils which are no more than 50,000 years old.

• C14

• U238

• K40

• Rb87

What does organic mean?

• something that was once living or still living and also referred to as biologic

• something that is made of metal

• everything is organic

After one half-life how much of the parent and daughter is left?

• 75% parent

  25% daughter

• 50% parent

  50% daughter

• 75% daughter

  25% parent

Tags

NGSS.HS-PS1-8

After 4 half lives, how many years has passed?

• 5,700

• 22,800

• 25,808

Tags

NGSS.HS-PS1-8

Reorder the following

• An organism is no longer alive and we call this time zero

• after 11,400 years this fossil has 25% carbon 14 and 75% nitrogen 14

• after 5,700 years this fossil has 50% carbon 14 and 50% nitrogen 14

• After about 50,000 years carbon 14 is undetectable in the organism

• the organism contains carbon 14 which now begins to disintegrate into nitrogen 14

Uranium 238 is used to determine the ​ ​ (a)  

• age of the Earth
• the age of a mammoth

Tags

NGSS.HS-ESS1-6