Average Atomic Mass

Front

What is average atomic mass?

Back

The weighted average of the masses of an element's isotopes, taking into account their relative abundance.

Front

How do you calculate average atomic mass?

Back

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

Front

What is an isotope?

Back

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

What is the symbol for an isotope?

Back

The symbol includes the element's symbol, the mass number (total protons and neutrons), and the atomic number (number of protons).

Front

If an element has isotopes with masses of 10 amu (50%) and 12 amu (50%), what is the average atomic mass?

Back

11 amu.

Front

What is the most abundant isotope of nitrogen?

Back

Nitrogen-14.

Front

What does the term 'relative abundance' mean?

Back

The percentage of a particular isotope compared to the total amount of all isotopes of that element.

Front

Calculate the average atomic mass of an element with isotopes: 24.1% at 75.23 amu, 48.7% at 74.61 amu, and 27.2% at 75.20 amu.

Back

74.92 amu.

Front

What is the difference between atomic mass and average atomic mass?

Back

Atomic mass is the mass of a single atom, while average atomic mass is the weighted average of all isotopes of an element.

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom, which defines the element.