Why does Ammonium ion have a +1 charge?

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Aleksander Krol
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The total valence electrons for NH4+ is 5+4(1)-1=8e-
so Nitrogen has 5e- and 4 Hydrogens, each with 1 e-
One of the Hydrogen loses an electron rather than Nitrogen, is because Hydrogen is less electronegative than Nitrogen so it has a tendency to lose electrons. so one of the Hydrogen loses and forms +1 charge.
Nitrogen have 1 pair (2e-) left after forming 3 single bonds with 3 Hydrogens. So Nitrogen gives 1e- from its lone pair to H+ ion and now H+ will have a charge of -1, cause it accepted 1e- from Nitrogen.
And now Nitrogen will have +1 charge, cause it gave 1e- to H+.
Nitrogen now has 1 e- left in its valence after giving away 1e- from it's lone pair. I believe this part to be dative bonding.
Alright, so now Nitrogen forms a single bond with H- using its last electron left on its valence.
So Nitrogen now has a formal charge of +1, and one of the 4 Hydrogens from NH4 has a charge of -1 after accepting an electron from Nitrogen and the rest three Hydrogens have a charge of 0.
So, here's my problem, when we add all the formal charges in NH4, we're supposed to get +1.
But over here when I add them all up +1+(-1)=0
I get 0
Am I missing something out?
Can someone please help me understand this?
I'd appreciate it a lot :3
Last edited by Aleksander Krol; 3 weeks ago
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flaurie
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(Original post by Aleksander Krol)
So, here's my problem, when we add all the formal charges in NH4, we're supposed to get +1.
But over here when I add them all up +1+(-1)=0
I get 0
Am I missing something out?
Can someone please help me understand this?
I'd appreciate it a lot :3
I only did chemistry up to gcse level so if this beyond that then ignore me

Nitrogen has an ionic charge of 3- and hydrogen has an ionic change of 1+, so NH4 would be 3- and 4 lots of 1+ which would give you an overall 1+ charge
Last edited by flaurie; 3 weeks ago
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Aleksander Krol
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(Original post by flaurie)
I only did chemistry up to gcse level so if this beyond that then ignore me

Nitrogen has an ionic charge of 3- and hydrogen has an ionic change of 1+, so NH4 would be 3- and 4 lots of 1+ which would give you an overall 1+ charge
i'm using my brother's account, and i'm doing my gcses. ig i'm over thinking about this XD, but anyways, thanks <3 ig so that's the answer.
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bl0bf1sh
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try drawing a dot-cross diagram of NH4+
there will be a "spare electron" which is lost, hence the single positive charge
or, think of it as ammonium (NH3) gaining a proton (= hydrogen ion, H+)

Spoiler:
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chemguide has this rather good illustration, it shows where the electrons are from
Name:  Screenshot 2021-09-20 at 18.54.54.png
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Size:  106.6 KB
don't worry about the term 'coordinate bond', this just means that both the electrons in the covalent bond have come from the same atom (the nitrogen), something that comes up at a level
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Aleksander Krol
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(Original post by bl0bf1sh)
try drawing a dot-cross diagram of NH4+
there will be a "spare electron" which is lost, hence the single positive charge
or, think of it as ammonium (NH3) gaining a proton (= hydrogen ion, H+)

Spoiler:
Show
chemguide has this rather good illustration, it shows where the electrons are from
Name:  Screenshot 2021-09-20 at 18.54.54.png
Views: 6
Size:  106.6 KB
don't worry about the term 'coordinate bond', this just means that both the electrons in the covalent bond have come from the same atom (the nitrogen), something that comes up at a level
omg thanks a lot!!
i learned about coordinate bond, so it's okay.
actually that's the place i'm sort of a bit perplexed. so i watched this video explaining about the lewis structure of nitrate ion where she gives a negative charge on the oxygen because nitrogen gives 1 e- to one of the oxygen via dative bonding, leaving nitrogen with +1 and that oxygen -1 charge.
https://www.youtube.com/watch?v=D608NzB8Mr8&t=162s
so if H+ ion gains 1 electron, will it be H- or just H?
Last edited by Aleksander Krol; 3 weeks ago
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scimus63
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ammonium is made by adding a positive hydrogen ion to a neutral ammonia molecule. If you add a positive charge to a neutral molecule the molecule will not be neutral - it will have a positive charge! The charge is spread over the whole molecule, so just draw your dot and cross diagram with nitrogen making 4 bonds but as I said the charge is over the whole molecule.

Nitrate ions are different I think - they are resonance stabilised ions.
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Aleksander Krol
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(Original post by scimus63)
ammonium is made by adding a positive hydrogen ion to a neutral ammonia molecule. If you add a positive charge to a neutral molecule the molecule will not be neutral - it will have a positive charge! The charge is spread over the whole molecule, so just draw your dot and cross diagram with nitrogen making 4 bonds but as I said the charge is over the whole molecule.

Nitrate ions are different I think - they are resonance stabilised ions.
okay, thanks!! <3
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