Radioactive Decay and Half-Life Concepts

The lecture introduces radioactive decay, explaining how unstable nuclei transform into more stable forms. It covers the types of decay: alpha, beta, gamma, positron emission, and electron capture, along with their nuclear equations. The concept of decay series and half-lives is discussed, highlighting how these principles help determine the age of materials, such as rocks and organic matter, using methods like carbon dating.

What is the term used for the original unstable nucleus in radioactive decay?

• Parent nucleus

• Daughter nucleus

• Alpha nucleus

• Beta nucleus

Which of the following particles is positively charged?

• Gamma ray

• Neutron

• Beta particle

• Alpha particle

In beta decay, what happens to a neutron?

• It becomes an alpha particle

• It becomes a gamma ray

• It becomes a proton and an electron

• It becomes a proton and a positron

What is the change in atomic mass during alpha decay?

• Increases by 4

• Decreases by 4

• Increases by 2

• Decreases by 2

How is the half-life of a radioactive element defined?

• Time for double the material to decay

• Time for a quarter of the material to decay

• Time for all material to decay

• Time for half the material to decay

If you start with 20 grams of a substance with a half-life of 5 years, how much remains after 10 years?

• 10 grams

• 2.5 grams

• 5 grams

• 1.25 grams

What is the primary use of carbon-14 dating?

• Dating gases

• Dating rocks

• Dating organic materials

• Dating metals

Which element is used in dating rocks with a half-life of 4.5 billion years?

• Argon

• Potassium

• Uranium

• Carbon

What is the ratio of argon to potassium in a moon rock that indicates an age of 4.3 billion years?

• 3:1

• 11:1

• 1:11

• 7:1

Which of the following is NOT a type of radioactive decay?

• Alpha decay

• Beta decay

• Gamma decay

• Delta decay