Argon

Properties

Atomic number

18

Atomic mass

39.948 u

Category

noble gas

Group

18

Period

3

Block

p-block

State (room temp)

Gas

Outer-shell electrons

8

Electronegativity

-

Density

-

Melting point

-189.34 °C

Boiling point

-185.85 °C

About Argon

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).

• Discovered by Lord Rayleigh
• Appearance: colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field

Argon: frequently asked questions

What is Argon?

Argon (Ar) is the chemical element with atomic number 18. It is a nonmetal: specifically a noble gas, the group with full outer electron shells.

What is the atomic number of Argon?

Argon's atomic number is 18, which means every Argon atom has 18 protons in its nucleus.

What is the electron configuration of Argon?

The electron configuration of Argon is 1s2 2s2 2p6 3s2 3p6 (noble-gas shorthand: [Ne] 3s2 3p6). Its electrons are arranged in shells of 2, 8, 8, with 8 in the outermost shell.

Is Argon a metal or a nonmetal?

Argon is a nonmetal: specifically a noble gas, the group with full outer electron shells.

What group and period is Argon in?

Argon is in group 18 and period 3 of the periodic table.

Is Argon a solid, liquid, or gas?

At room temperature, Argon is a gas.

Position in the periodic table

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