Radioactive Decay and Isotopes

The video tutorial from Homk Middle School's Earth Science Department explains radioactive decay and its role in determining the absolute age of rock samples. It covers the basics of atomic structure, isotopes, and how isotopes decay into daughter products over time. The tutorial highlights key isotopes like carbon-14, potassium-40, uranium-238, and rubidium-87, explaining their half-lives and applications in dating organic materials and rocks. The video emphasizes the predictability of decay rates and the concept of half-life, illustrating how these principles are used to determine the age of geological samples.

What is the primary benefit of understanding radioactive decay in geology?

• It predicts weather patterns.

• It determines the actual age of rock samples.

• It helps in identifying the color of rocks.

• It measures the density of minerals.

Which part of the atom is considered the 'brain'?

• Nucleus

• Proton

• Electron

• Neutron

What distinguishes an isotope from a stable element?

• Different number of electrons

• Different atomic number

• Different number of neutrons

• Different number of protons

Which isotope is used to date organic material up to 50,000 years old?

• Potassium-40

• Uranium-238

• Carbon-14

• Rubidium-87

What is the decay product of Carbon-14?

• Calcium-40

• Nitrogen-14

• Strontium-87

• Lead-206

How long is the half-life of Potassium-40?

• 49 billion years

• 42 billion years

• 1.3 billion years

• 5,700 years

What does the half-life of an isotope indicate?

• The time it takes for the isotope to double in mass.

• The time it takes for the isotope to become stable.

• The time it takes for half of the isotope to decay.

• The time it takes for the isotope to change color.

Which isotope has a half-life longer than the age of the universe?

• Potassium-40

• Rubidium-87

• Carbon-14

• Uranium-238

What is true about the decay rates of isotopes?

• They can be reversed by changing temperature.

• They are predictable and irreversible.

• They vary with pressure changes.

• They depend on the mass of the sample.

In a decay curve, what happens to the mass of the isotope over time?

• It increases.

• It remains constant.

• It decreases.

• It fluctuates randomly.