Xenon

Xenon is a chemical element, having the chemical symbol Xe.

Xenon 131.293(6)   Xe 54 [Kr] 4d10 5s2 5p6 [ ? ] Noble gas:

Its atomic number (the number of protons) is 54. It has a Standard Atomic Weight of 131.293(6), and is typically found as a gas in its elemental form.

Xenon is considered to be a member of the "Noble gas" class of elements, has a boiling point of -108.12 °C , and a melting point of -111.79°C .

Xenon 131.293(6)   Xe 54 1s22s22p63s23p63d10 4s24p64d105s25p6 54,5, [ ? ] Noble gas:

¹³¹Xe, while radioactive, is a relatively safe breakdown product of ¹³¹Iodine.