[student777888]

Why will a Hydrogen ion form a dative covalent bond with a Ammonia atom but not with a noble gas atom when both atoms would have a full outer shell?

I asked my tutor this question and he did not know :~/

Thanks for any help.

[Sircodekill]

Why will a Hydrogen ion form a dative covalent bond with a Ammonia atom but not with a noble gas atom when both atoms would have a full outer shell?

I asked my tutor this question and he did not know :~/

Thanks for any help.

i cant believe your teacher didn't know the difference about NH₃ and Ne.

Nitrogen oxidation state can go from +5 to -3, the last means ammonia when is combined with hydrogen. Ammonia has a lone pair of electrons where protons (H⁺) gets attracted. It's like 2 magnets, and they get attracted when are put together.
Therefore, now ammonium will not react with more protons, as a noble gas does. A noble gas doesn't work as a magnet.

[student777888]

What causes the 2 electrons to act as magnets as ammonia would have 10 protons and 10 electrons with the outer shell full. Would it not be making itself more unstable by becoming a Ammonium ion. Why could neon not attract 4 hydrogen ions?

[Borek]

Nitrogen oxidation state can go from +5 to -3, the last means ammonia when is combined with hydrogen.

I feel like you didn't understand the question. most of what you wrote either is irrelevant to the problem, or simply wrong.

Ammonia has a lone pair of electrons where protons (H⁺) gets attracted.

Nitrogen in ammonia has a lone pair, oxygen in water has two (and protonated form H₃O⁺ is well known), fluorine in HF has three (and protonated form H₂F⁺ is well known), following this logic Ne has four lone pairs. Question is: why don't these react with H⁺, why HNe⁺ doesn't exist?

[student777888]

^^^^

This is what i was asking thanks.

[student777888]

Do not know if this is correct but seems to make sense.

Ammonia would be a polar compound so would attract the hydrogen ion. This would give it a tetrahedral shape to remove the polartity. A noble gas would not have this problem.

Is there a flaw to this logic?

[Sircodekill]

I've been thinking on this for 2 days, but I'm sorry, I don't know the answer. I think its about molecular orbitals and it's space. Anyway, HNe^7- exists. You need to empty all 2s² and 2p⁶ to do this. Then the 1s² acts as dative bond.

H₃O⁺ and NH₃ are isoelectronic and they are both polar.