Periodic table / Argon

Overview

Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most common gas in the Earth's atmosphere, at 0.934% (9,340 ppmv), making it over twice as abundant as the next most common atmospheric gas, water vapor (which averages about 4000 ppmv, but varies greatly), and 23 times as abundant as the next most common non-condensing atmospheric gas, carbon dioxide (400 ppmv), and more than 500 times as abundant as the next most common noble gas, neon (18 ppmv).

Electron configuration

The electron configuration of Argon is [Ne] 3s2 3p6, with electron shells of 2, 8, 8.

Physical and chemical properties

Argon is classified as a noble gas. It has an atomic mass of 39.948 and exists as a gas at standard conditions, appearing as colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field.

Real-world uses of Argon

As a noble gas, Argon is chemically inert and is primarily used in lighting, insulation, or specialized industrial and scientific applications.

Interesting facts about Argon

• Argon has the atomic number 18 and chemical symbol Ar.
• It belongs to period 3, group 18 of the periodic table.
• Argon was discovered by Lord Rayleigh.

Explore Argon interactively

Want to compare Argon with other elements or see it highlighted on the full table? Open the interactive periodic table and click on Ar to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.