Krypton is a chemical element, symbol Kr , atomic number 36. It’s a colorless, odorless, mostly inert noble gas found in trace amounts in the air and used in some lighting and laser applications.

Quick Scoop

  • What it is: A noble gas in Group 18 of the periodic table.
  • What it’s like: Heavy, colorless, odorless, and very unreactive.
  • Where it’s used: Fluorescent lamps, flash lamps, some lasers, and as part of the historical definition of the meter.
  • Fun fact: Its name comes from the Greek word for “hidden,” because it occurs only in tiny amounts in the atmosphere.

In Simple Terms

If you imagine the periodic table as a cast of characters, krypton is one of the “quiet” ones: it usually doesn’t react with other elements and just floats around in the air in very small amounts. That’s why it’s useful in specialized lighting rather than everyday chemistry.

Bottom line

Krypton is a rare noble gas with atomic number 36, known for being chemically unreactive and useful in lighting and laser tech.