Helium is the lightest noble gas. It was discovered in 1868 by Sir J. Norman Lockyer in wavelength analysis of the sun. The name is based on the Greek Helios, meaning sun. Helium is also a nonrenewable resource, which is running out.
Neon is the next noble gas in the periodic group. It was discovered in 1898 by Morris Travers and Sir William Ramsay. The bright lights known as neon lights use neon to give off an orange glow.
Argon was discovered in 1894 by Lord Rayleigh and Sir William Ramsay. Argon is lighter than nitrogen and easily dissolved in water. Argon is common on Earth and is a cheaper alternative to the other noble gases.
Krypton was also discovered by William Ramsay using the same experiment that led to the discovery of neon. Krypton is used in energy efficient windows as insulation and in light bulbs.
Xenon, like neon,krypton and argon, was discovered by William Ramsay in 1898. X-rays are improved by the use xenon, and is used in other purposes, such as incandescent lighting, used in car headlights and plasma video displays.
Radon was discovered in 1900 during studies of a radioactive gas. Homes and buildings are tested for radon levels because radon is highly carcinogenic inhaled. Radon is the second leading cause of lung cancer after smoking.