Nuclear Decay and Half-Life

The half-life of a radioactive isotope is 20.0 minutes. What is the total amount of a 1.00-gram sample of this isotope remaining after 1.00 hour?

• 0.500g

• 0.333g

• 0.250g

• 0.125g

Tags

NGSS.HS-PS1-8

The technetium-99 isotope has a half-life of 6.0 hours. If 100.0 mg were injected into a patient how much remains after 18 hours?

• 33.0 mg

• 12.5 mg

• .33 mg

• 15.8 mg

Complete the nuclear equation and determine the type of decay that is occurring in this reaction. 

• alpha

• beta

• gamma

• none

Tags

NGSS.HS-PS1-8

If we start off with element ₂₄X⁵⁰ after an alpha decay we get another element Y that looks like

• ₂₂Y⁵⁰

• ₂₂Y⁴⁶

• ₂₀Y⁴⁸

• ₂₆Y⁵⁴

Tags

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 an isotope if after 20.0 days you have 4.0 grams remaining of a 64.0 grams sample?

• 25 days

• 5.0 days

• 0.000305 days

• 4.25 days

Which type of radiation has the greatest penetrating power?

• Alpha

• Beta

• Gamma 

• Microwaves

Why does an atom undergo beta decay?

• It has too many electrons.

• It has an atomic number greater than 83

• It has more neutrons than protons

• It has more protons than neutrons

Tags

NGSS.HS-PS1-8

What happens to the atomic number during alpha decay?

• The atomic number decreases by 4

• The atomic number increases by 1

• The atomic number decreases by 2.

• The atomic number stays the same.

Tags

NGSS.HS-PS1-8

Arrange in order of increasing ability to penetrate matter.

• Beta, gamma, alpha

• Alpha, gamma, beta

• Gamma, beta, alpha

• Alpha, beta, gamma

Tags

NGSS.HS-PS1-8