Isotopes, Half Life, Average atomic Mass Flashcard

Front

What is an isotope?

Back

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

Front

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

Back

Number of neutrons = Mass number - Number of protons.

Front

What is half-life?

Back

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

Front

If an isotope has a half-life of 10 years, how much of a 100g sample remains after 30 years?

Back

After 30 years (3 half-lives), 12.5g of the sample remains.

Front

What is average atomic mass?

Back

Average atomic mass is the weighted average of the atomic masses of an element's isotopes, taking into account their relative abundances.

Front

How do you find the average atomic mass of an element with multiple isotopes?

Back

Multiply the atomic mass of each isotope by its relative abundance (as a decimal), then sum these values.

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 isotopes and atomic mass?

Back

Isotopes of an element have different atomic masses due to differing numbers of neutrons.

Front

Which isotope of oxygen is most abundant in nature?

Back

O-16 is the most abundant isotope of oxygen.

Front

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

Back

The mass decreases as the substance decays over successive half-lives.