Noble gases or inert gases, are six gaseous elements found in small amounts in the Earth’s atmosphere. They include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). This group of gases are only one percent of the Earth’s atmosphere. These gases were discovered by scientists in the late 1800s, and because they were so unreactive were initially referred to as inert gases. Although noble gases are often used to describe these elements, they are only rare in abundance relative to other gases found in the atmosphere of Earth.

Group 18 on the Periodic Table
The noble gases form the group 18 of the periodic table of elements, shown on the extreme right side. The rare gases are placed in the same group because their elements reflect similar properties. These noble gases are monatomic gases as they exist as individual atoms, and are all colorless, odorless, and tasteless.