Definition:Krypton
Chemical Element
Krypton is the chemical element that has $36$ protons in the nuclei of its atoms
Its chemical symbol is $\text {Kr}$.
Isotopes
Kr-$82$
Krypton-$82$ is the isotope of krypton which has $46$ neutrons in addition to its $36$ protons.
Kr-$82$ is the third most common stable isotope of krypton, making up $11.6 \%$ of the krypton found on Earth.
Kr-$83$
Krypton-$83$ is the isotope of krypton which has $47$ neutrons in addition to its $36$ protons.
Kr-$83$ is the least common stable isotope of krypton, making up $11.5 \%$ of the krypton found on Earth.
Kr-$84$
Krypton-$84$ is the isotope of krypton which has $48$ neutrons in addition to its $36$ protons.
Kr-$84$ is the most common stable isotope of krypton, making up $57.0 \%$ of the krypton found on Earth.
Kr-$86$
Krypton-$86$ is the isotope of krypton which has $50$ neutrons in addition to its $36$ protons.
Kr-$86$ is the is the second most common stable isotope of krypton, making up $17.3 \%$ of the krypton found on Earth.
Linguistic Note
The word krypton was taken from the Greek κρυπτός, meaning the hidden one.