Xenon

Xenon (Xenon, Heh) is a chemical element zero of the group of the periodic system of D. I. Mendeleev.
Serial number 54, atomic weight 131,3. In nature xenon is only in a free state. In the dry ambient air contains about 0,000009% by weight. Get as admixture to krypton (see). Monatomic gas. Chemically inactive (inert gas). Practical value for radioisotope diagnostics (see) has Xe133. Cm. also, MRI, nuclear medicine.