# Which halogen forms the strongest bond with hydrogen to form HX?

The strongest $H - X$ bond is definitely between hydrogen and fluorine. Fluorine is a first row element; it makes sense that there is better overlap between fluorine/hydrogen orbitals, than between chlorine/hydrogen orbitals. The strength of the $H - F$ bond is well illustrated by the acidity of the hydrohalic acids. $H - C l$, and $H - B r$ undergo almost complete dissociation in water; they are strong acids. $H - F$ is considered to be a weak water acid in that the smaller fluorine atom tenaciously binds to the proton.
As a physical scientist you should look up the numbers, and look at the $p {K}_{a}$'s of the hydrohalic acids.