What Are Atoms Made Of?

Atoms are the basic building block of elements.

Atoms are the basic unit for building molecules. Atoms join together with other atoms to create compounds.

Composition

Atoms are composed of neutrons, electrons and protons. Electrons have a negative charge, protons have a positive charge and neutrons have no charge.

Location

The protons and neutrons are located in the nucleus of the atom, and the electrons orbit the nucleus.

Size

The size of an atom can only be estimated and is thought to be as large as 0.3 nanometers. A neutron is about the same mass as protons. Protons and neutrons are more than 1,800 times bigger than an electron.

History

The first person to conceive of an atom was John Dalton, an English chemist. In 1897,
J.J. Thomson, an English physicist, was the first to propose a model of the atom.

Fun Fact

There are 90 atoms that are formed without human intervention. Laboratories have succeeded in creating an additional 25.

References

• What are Atoms?
• History of Atoms
• All About Atoms

Resources

• Purdue Chemistry Department