A Noble Gas is a type of gas that is found in the Earth's atmosphere. The four most common Noble Gases are NEON (4 letters), ARGON (5 letters), XENON (5 letters), and RADON (5 letters). NEON is a colorless, odorless, and tasteless gas that is used in lighting and advertising signs. ARGON is a colorless, odorless, and tasteless gas that is used in welding and other industrial processes. XENON is a colorless, odorless, and tasteless gas that is used in medical imaging and lasers. RADON is a radioactive gas that is found naturally in the environment and can be hazardous to human health.