The trend in electron affinity is to increase negatively across a group.
Does this mean noble gases' electronegativity is more negative than halogens?
Noble gases should have a positive electron affinity as adding an electron would make it unstable and thus will not happen.
But for halogens the attraction for that one electron to fill up the $\mathrm{p}$ subshell is very strong.
But given the theory that electron affinity increases negatively across the period, does this theory make an exception for noble gases?
Next, what about $\ce{Be}$ and $\ce{Mg}$? Their electron affinities are not negative.