The Basics:
Name: krypton
Symbol: Kr
Atomic number: 36
Atomic weight: 83.80(1) g m
CAS Registry ID: 7439-90-9
Group number: 18
Group name: Noble gas
Period number: 4
Block: p-block
Standard state: gas at 298 K
Color: colorless

DESCRIPTION:
Krypton is present in the air at about 1 ppm. The atmosphere of Mars contains a little (about 0.3 ppm) of krypton. It is characterised by its brilliant green and orange spectral lines. The spectral lines of krypton are easily produced and some are very sharp. Under normal conditions krypton is colourless, odourless, fairly expensive gas. Solid krypton is a white crystalline substance with a face-centered cubic structure which is common to all the "rare gases".

The diagram is of a Krypton atom
ISOLATION:
Krypton is present to a small extent (about 1 ppm by volume) in the atmosphere and is obtained as a byproduct from the liquefaction and separation of air. This would not normally be carried out in the laboratory and krypton is available commercially in cylinders at high pressure.