About the electronegativity of Xe

Well, Noble gas group is not well-studied. let me explain a little bit.

1) traditionally, electronegativity is used for describing the ability of an atom, to attract electrons to itself, when combined with other atoms. Noble gas, in HKAL syllabus, still use this for explain the possibility of covalent bond formation, which is insufficient.

2) To describe noble gas reaction, we should understand the molecular orbitals theory, e.g. bonding, anti-bonding, overlapping of orbitals (not simply octet rule forms sigma, pi bonds, etc), transistion of (quasi-)quantum energy levels in each orbitals, etc.

3) Xe, has more compounds such as XeF2, (XeF)3-, XeF4, (XeF5)2-, (XeF6)2-, etc. Krypton, Argon and Rn also form fluoride compounds, such as RnF2, KrF2, ArF2. This is due to the resonance electrons within the quantum energy levels allow transition of electron from noble gas atom to fluoride and vice versa. To allow such reaction occur, some catalyst like PtF2 or low temperature may be needed, depends on situation

4) After year 2000, some simulation has been done on such compounds and people successfully synthesis some more noble gas compounds such as HXeCl, HArCl. The reaction normally need high pressure in the presence of noble gas environment.

5) exact explanation for noble gas compounds still not validated because we don;t have sufficient number of "man-made" compounds to study... So, don't affine yourself in electronegativity for explanation.