Stable

The video discusses the concept of stability in materials, particularly focusing on isotopes that are not susceptible to decay or have extremely long radioactive half-lives. It explains how these isotopes are stable over long periods and are not easily changed by decay processes.

What does it mean for something to be not susceptible to decay?

• It is highly reactive.

• It changes rapidly over time.

• It remains unchanged over a long period.

• It is easily broken down.

In what context is the term 'not susceptible to decay' often used?

• In reference to physical changes.

• In reference to biological processes.

• In reference to isotopes.

• In reference to chemical reactions.

What is a characteristic of isotopes that do not show radioactive decay?

• They emit visible radiation.

• They have immeasurable half-lives.

• They are highly unstable.

• They have short half-lives.

What is a radioactive half-life?

• The time it takes for a substance to double its radioactivity.

• The time it takes for half of a radioactive substance to decay.

• The time it takes for a substance to become radioactive.

• The time it takes for a substance to lose all its radioactivity.

Why might some isotopes have half-lives that are too long to measure?

• They emit too much radiation.

• They are not radioactive.

• They decay too quickly.

• They are extremely stable.