h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

There are a few bits wrong here:
Group 18, the noble gases, can form compounds. I recall oxidation states of +8 or + 4.
Group 8 transition metals, such as Osmium, can also be +8
Group 17 halogens can be +1 (e.g. ClO-, the chlorate (I) ion)

My understanding is that where a covalent bond exists between atoms in a compound, for the purposes of oxidation number assignment the bond is broken with both electrons being assigned to the more electronegative atom: H-Cl becomes H+ and Cl-

This does then beg the question of which element is more electronegative, especially if we treat electronegativities as dependent on the chemical state of the atom (O being more electronegative than O- for example).

At this point, even I'm not pedantic enough to stay awake...