Nuclear and Stars 24H

Front

What is the half-life of a radioactive substance?

Back

The half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

How do you calculate the number of half-lives that have passed?

Back

Divide the total time elapsed by the half-life of the substance.

Front

What force causes a nebula to collapse into a protostar?

Back

Gravity is the force that causes a nebula to collapse and form a protostar.

Front

How do you determine the number of neutrons in an isotope?

Back

Subtract the atomic number (number of protons) from the mass number of the isotope.

Front

What is the mass number of an isotope?

Back

The mass number is the total number of protons and neutrons in the nucleus of an atom.

Front

What is the atomic number of an element?

Back

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

Front

What is the relationship between protons and neutrons in an isotope?

Back

Isotopes of an element have the same number of protons but different numbers of neutrons.

Front

How much of a substance remains after two half-lives?

Back

After two half-lives, one-fourth (25%) of the original amount remains.

Front

What is the significance of the term 'isotope'?

Back

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons.

Front

What happens to the mass of a radioactive substance over time?

Back

The mass decreases as the substance decays over time.