Inert gases are a group of elements that are chemically unreactive and have low boiling points. The most common inert gases are ARGON, XENON, RADON, NEON, HELIUM, KRYPTON, and niton. ARGON is a colorless, odorless gas that is the most abundant in Earth's atmosphere. XENON is a colorless, odorless gas that is used in lighting and lasers. RADON is a radioactive gas that is found in soil and rocks. NEON is a colorless, odorless gas that is used in NEON signs. HELIUM is a colorless, odorless gas that is used in balloons and blimps. KRYPTON is a colorless, odorless gas that is used in fluorescent lamps. Niton is a colorless, odorless gas that is used in some medical treatments.