Give similarities between beryllium and aluminum metal.

(N/A) The ionic radius of $Be^{2+}$ is estimated to be $31 \ pm$; the charge/radius ratio is nearly the same as that of the $Al^{3+}$ ion. Hence,beryllium resembles aluminium in some ways. Some of the similarities are:
$(i)$ Like aluminium,beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal.
$(ii)$ Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion,$[Be(OH)_{4}]^{2-}$,just as aluminium hydroxide gives an aluminate ion,$[Al(OH)_{4}]^{-}$.
$(iii)$ The chlorides of both beryllium and aluminium have $Cl^{-}$ bridged chloride structures in the vapour phase. Both the chlorides are soluble in organic solvents and are strong Lewis acids. They are used as Friedel-Crafts catalysts.
$(iv)$ Beryllium and aluminium ions have a strong tendency to form complexes like $[BeF_{4}]^{2-}$ and $[AlF_{6}]^{3-}$.