Xenon is the element with larger atomic number (i.e. heavier element) in the inert gas, and the xenon atomic radius is larger. The atomic number is 54, the peripheral electron arrangement is 5s2 5p6, which is located in the fifth cycle 18 family (IUPAC new regulations, namely the original 0 family), the atomic covalent radius is 209 picometers, and the first ionization energy is 1172 kJ/mol.