Krypton is named after the Greek word that means “secret.” Which explains why krypton was most likely given this name?

Krypton is a halogen, so it is a secret element because it is always part of a compound and is difficult to find by itself.
Krypton is a halogen, so it should be kept secret because it is so reactive and toxic.
Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.
Krypton is a noble gas, so it secretly bonds with every type of element without showing it.