Which noble gas with atomic number 36 is used in some flash lamps? Krypton is the answer.
Krypton is a colorless, odorless, chemically inert noble gas whose symbol is Kr. Its name comes from the Greek word kryptos, meaning “hidden,” reflecting its trace-level presence in Earth’s atmosphere. William Ramsay and Morris Travers discovered it in 1898 while examining the gases left after liquefying air.
Krypton’s distinctive emission lines make its electrical discharge appear nearly white. That makes it useful in certain photographic flash lamps, especially equipment designed for high-speed photography. It is also used in some fluorescent lamps, incandescent bulbs, and specialized lasers.
A common mix-up is xenon, which is also widely associated with bright photographic flashes and vehicle headlights. Neon is best known for brightly colored signs, while argon is more abundant and cheaper. Krypton’s atomic number, 36, distinguishes it from these neighboring noble gases.