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.

Front

How is atomic mass calculated?

Back

Average atomic mass is calculated by taking the sum of the products of the atomic mass of each isotope and its percent abundance.

Front

What does it mean for an atom to be electrically neutral?

Back

An atom is electrically neutral when the number of protons equals the number of electrons.

Front

What is the atomic mass of carbon-12?

Back

The atomic mass of carbon-12 is defined as exactly 12 atomic mass units (amu).

Front

What is the average atomic mass of an element with two isotopes: 10.013 amu (19.9% abundance) and 11.01 amu (80.1% abundance)?

Back

The average atomic mass is 10.812 amu.

Front

What is the difference between carbon-12 and carbon-14?

Back

Carbon-12 and carbon-14 differ in the number of neutrons; carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons.

Front

What is percent abundance?

Back

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

Front

Which atom has 4 neutrons: Li-6, Li-7, or Li-8?

Back

Li-7 has 4 neutrons.

Front

What is the significance of the atomic number?

Back

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

Front

How do isotopes of the same element differ?

Back

Isotopes of the same element differ in their mass number due to a different number of neutrons.