Isotopes and Calculating Atomic Mass

Front

What is an isotope?

Back

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

Front

How do you calculate the average atomic mass of an element?

Back

To calculate the average atomic mass, multiply the atomic mass of each isotope by its percent abundance (as a decimal), then sum these values.

Front

What is the mass number of an atom?

Back

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

Front

What does the atomic number represent?

Back

The atomic number represents the number of protons in the nucleus of an atom and determines the element's identity.

Front

How many protons are in the isotope Titanium-48?

Back

Titanium-48 has 22 protons.

Front

What is the percent abundance of an isotope?

Back

Percent abundance is the relative amount of a particular isotope of an element compared to the total amount of all isotopes of that element, expressed as a percentage.

Front

If an isotope has a mass of 39.946 amu and a percent abundance of 4.35%, how do you include it in the average atomic mass calculation?

Back

Multiply 39.946 amu by 0.0435 (the decimal form of 4.35%) to find its contribution to the average atomic mass.

Front

What is the relationship between neutrons and isotopes?

Back

Isotopes of an element differ in the number of neutrons, which affects their atomic mass but not their chemical properties.

Front

What is the formula for calculating average atomic mass?

Back

Average Atomic Mass = (mass of isotope 1 × percent abundance of isotope 1) + (mass of isotope 2 × percent abundance of isotope 2) + ...

Front

How many neutrons does Lithium-7 have?

Back

Lithium-7 has 4 neutrons (7 mass number - 3 protons = 4 neutrons).