Why does Xe in XeF4 have 12 electrons in lewis structure?
Well, xenon is the central atom..........
And formally has 8 valence electrons; and four bonding electrons derive from the 4 fluorine atoms. The result? There are 6 electron-pairs, bonding and non-bonding, to distribute around the central xenon atom, and a square planar geometry results inasmuch as we describe geometry on the basis of the disposition of atoms, not on the disposition of electron pairs (which assume an octahedral geometry).