Isotopes and Calculating Atomic Mass

Front

What is an isotope?

Back

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

What do isotopes of an element have in common?

Back

Isotopes of an element have the same atomic number and electrons.

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

How do isotopes differ from each other?

Back

Isotopes differ in their number of neutrons and therefore have different atomic masses.

Front

What is atomic mass?

Back

Atomic mass is the weighted average mass of an element's isotopes, measured in atomic mass units (amu).

Front

What is the formula to calculate 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

If an isotope has 22 protons, what element is it?

Back

It is titanium (Ti), as titanium has an atomic number of 22.

Front

What is percent abundance in relation to isotopes?

Back

Percent abundance is the relative amount of each isotope of an element in a sample, expressed as a percentage.

Front

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

Back

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

Front

What is the average atomic mass of an element with 4.35% of atoms at 39.946 amu, 83.79% at 41.941 amu, 9.50% at 42.941 amu, and 2.36% at 43.939 amu?

Back

The average atomic mass is 41.97 amu.