Krypton

Helium, neon, argon, krypton, xenon and radon are noble gases.

Our atmosphere contains 21% oxygen, which is necessary for us to breathe, 78% nitrogen, and 0.9% argon. The other 0.1% consists of water vapor, carbon dioxide, neon, methane, krypton, helium, xenon, hydrogen, nitrous oxide, carbon monoxide, nitrogen dioxide, sulfur dioxide, and ozone.

Krypton is an element 36 on the periodic table with symbol Kr.

In Grade 7, on one snowy winter day on Lulu Island, my friend Tom, who hailed from Taiwan, and I were building, on the school's baseball field, a snow city, modelled after the buildings on planet Krypton in the popular movie Superman with Christopher Reeve and Marlon Brando. Tom disappeared from this world later in high school.

Kryptonite comes from the planet Krypton.

Superman was born Kal-El on the planet Krypton.