Radiometric Dating

The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.

• the daughter product
• geologic time
• the half-life
• the half-time

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NGSS.HS-PS1-8

You find a rock sample with radioactive atoms present.  If 12.5% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)

• zero
• 1
• 2
• 3

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NGSS.HS-PS1-8

If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives?

• 25 years
• 200 years
• 400 years
• 800 years

Tags

NGSS.HS-PS1-8

The table shows the radioactive decay of carbon-14. Part of the table has been left blank. 
After 22,800 years, approximately what percentage of the original carbon-14 remains? 

• 15%
• 12.5%
• 6.25%
• 3.125%

Tags

NGSS.HS-PS1-8

An atom with a different number of protons and neutrons

• electrons

• isotopes

• ions

• reaction partners

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NGSS.HS-PS1-8

How many grams of Carbon-14 will remain after 17,100 years- C-14 has a half life 5,730 so 17,100 is about 3 half lives?

• 32 g

• 16 g

• 8 g

• 4 g

Tags

NGSS.HS-PS1-8

When an unstable radioactive atom decays, it usually turns into:

• a more stable atom

• a less stable atom

• the exact same atom but with less pure energy

• empty space

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NGSS.HS-PS1-8

Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?

• 0.25g
• 2.5g
• 25g
• 80g

What is the half-life of iodine-131?

• 32 days
• 8 days
• 16 days
• 24 days

Tags

NGSS.HS-PS1-8

What percent of carbon-14 would be left after 5730 years?

• 100%
• 75%
• 50%
• 25%

Tags

NGSS.HS-PS1-8