Question

How many halides are there?

Answer 1

Got a Periodic Table?

Explanation:

There are 5 common halides, fluoride, `F^-`, up to astatinide `At^-`.

I think there is the 1 trans-uranic element (a potential 6th halide), which is not really important, and would only be available in sub-milligram quantities.

Some ions are so-called pseudo-halides , e.g. `N_3^-` or `N-=C^-`.