I one plz

I one plz Boron forms(BF4)' but A1 forms do e;em.ents in the same group have similar e;ectron gain entha:pw,

Boron has Electronic configuration as: [He]2s²2p¹ and Aluminum as : [Ne]3s²3p¹

However Al has vacant 'd' orbitals and can expand its octet in [AlF₆]^- whereas, boron cannot expand its octet and hence gets restricted upto [BF₄]-

Regards,