The Student Room Group

Bond shapes - Chemistry

If ammonia accepts a H+ ion by forming a coordinate bond the shape will become tetrahedral with a bond angle of 109.5 degrees.

Comment on the relative strengths of all the N-H bonds in NH4+.

Im not understanding what it means by "relative strength" and wouldnt all the strengths be the same seeing as they will all be covalent bonds...??
Reply 1
i think it means compare the bond strength of N-H in ammonia and then the ammonium ion NH4+.

I would say the bond strength decreases as the bonds are closer to each other ?..could be wrong..sorry in advance
Reply 2
xskater
i think it means compare the bond strength of N-H in ammonia and then the ammonium ion NH4+.

I would say the bond strength decreases as the bonds are closer to each other ?..could be wrong..sorry in advance



I'd say that the bonds are stonger with NH4+ as the free pair of electrons are now occupied thus less electron repulsion. The NH bonds ARE NOT pushed closer together due to the rule of repulsion magnitude which goes

lone pair:lone pair> lone pair:bonded pair> bonded pair:bonded pair.

no free electrons are present as the H+ forms the dative covalent bond thus the lowest repulsion magnitude is feasible. BONDS THUS STRONGER.