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Posted

Is calcium carbonate a weak alkali?

it is yes.

 

Edit: and just to be a devil and make matters more confusing :)

have you ever considered H3O (yes H3O I didn`t make a mistake) as the conjugate Acid of water? LOL :))

Posted

Just imagine the ammonia molecule' date=' NH3.

If it is given one H , it should be NH4 , right?

But it is more stable when it lose one electron .

Therefore, it become NH4+.

[/quote']

 

Primarygun, according to your post, I think it was a little bit vague.....but the above part where says "loosing electron" inspires me abit....:P

 

The vague part is that since NH3 obtains a full outer shell valently, why it can be given one more H? Does not make sence to what I learned in chemistry....

 

So according to what I think is that the compound ion is cannot be formed individually without combining with other element.....

 

N has 5 electrons and it needs either give away 5 electrons or obtain 3 more electrons in order to form a full outershell in ionic bonding.

 

When H is combining in ionic way, it can only obtain electron, because if it looses one electron, then it obtains no electron any more, because it does not even have a shell, so

 

when H4 combining with N, it receives 4 electrons from N to form outer shell,

then N has one electron left....so it needs to be broken apart to combine with other element that needs one more electron to form outer shell..

 

THis is just what I think..

 

Any comments?

Posted

Actually, Hydrogen has ALL of the so-called electron shells. Just because they aren't filled doesn't mean that they don't exist. It's very possible that hydrogen could accept six electrons, but it's pretty much impossible since the attraction from the nucleus is VERY weak and the repulsion of the electrons would be VERY high. How do I know that hydrogen has more than just the 1s shell? Because hydrogen has an emission spectrum which occurs as the electron is excited into a higher energy level, then falls back down to the ground state.

 

As has been stated before, NH3 has a lone pair of electrons on the Nitrogen Atom. The geometry of the NH3 molecule is trigonal pyramidal with the lone pair very well exposed at the top. (Hence one of the reasons why ammonia is quite reactive). So when ammonia is formed, the three unpaired electrons in on Nitrogen will bond with the electrons present on Hydrogen, thereby giving both the Nitrogen atom and the hydrogen atoms filled shells. This is why NH3 is stable. However, if you were to put an H(+) ion near ammonia, the hydrogen ion would be just as stable, and maybe even a little bit more stable, if it had a full shell instead of an empty one. So it will easily be attracted to the lone pair of electrons on the nitrogen atom, thus forming the NH4(+) ion. Now all the atoms involved in the compound have completely full shells. This is why NH4(+) is so stable. However, it also has that charge of +1 which is why it will form ionic bonds with negatively charged ions.

Posted

I though of another idea.

What will be if three sodium is bonded to nitrogen atom?

Assume the geometry is the same, is the new molecule is more reactive than the ammonia molecule?

Posted
However, if you were to put an H(+) ion near ammonia, the hydrogen ion would be just as stable, and maybe even a little bit more stable, if it had a full shell instead of an empty one. So it will easily be attracted to the lone pair of electrons on the nitrogen atom, thus forming the NH4(+) ion. Now all the atoms involved in the compound have completely full shells. This is why NH4(+) is so stable. However, it also has that charge of +1 which is why it will form ionic bonds with negatively charged ions.

 

 

When H atom is near ammonia, does it loose electron to be attracted to the lone pair of N atom?

Posted

It has a probability.

However, bonded to form and to be stable to form is two different things.

I think the molecule is not very stable since it the central atom , nitrogen atom, need to spare a position for one lone electron and four pair electrons.

I have no longer knowledge on the stability. Therefore, I may be wrong.

Posted

so..... any way, the only thing I dont get yet is why NH4 ion in covalent bonding will be more stable than NH3 in covalent bonding?

 

Albert

Posted

YT, what??????????? Every one told me that the polyatomic ion in combination with another mono-atomic ion has both covalent (for polyatomic ion) and ionic bonding....,

but now you say the polyatomic ion is bonded in ionic?

 

Any way, I am asking: why NH4 ion in covalent bonding will be more stable than NH3 in covalent bonding?

 

Actually it appears not only in NH3 which strangely bonded in such way....like for eg, OH 1-, why it gives away one H? there is no point for this....

 

So, in my opinon, both OH and NH4 ion dont stay in this form individually since it is no reason scientifically for this, this ion only forms when there is energy exerting on them when in combination with other element in ionic bonding...

 

and on the contrary, I may be wrong....thats why I am asking you guys who study chemistry in unversity :)

 

Any body?

 

thx

 

Albert

Posted

nh4.gif

this is NH4

 

ammoniac.gif

this is NH3

 

the NH4 has more atoms pulling it together, imagine if each atom attracts each other x amount, then when you have NH4 there is more force between the atoms pulling them together then when there's NH3 and theres only 4 atoms pulling each other together (3 X H and 1 X N)

Posted

NH4 can only exist with a conjugate ( either acid or base, OH or NO3 for example) it can`t exist alone.

and NH5 can`t exist fullstop (lack of places for the H to occupy).

Posted

"and NH5 can`t exist fullstop (lack of places for the H to occupy)."

 

Got a mental image of five H sitting on a nitrogen atom, one of them saying "This place isn't big enough for the five of us". :)

Posted

yub yub guy with the long hair!!!! :D

 

theres a limit to everything.... and H4 is the limit to the amount of Hs a N can have!

Posted
yub yub guy with the long hair!!!! :D

 

theres a limit to everything.... and H4 is the limit to the amount of Hs a N can have!

 

 

5614, but how, how can you determine the limit of Hs an element can have in covalent bonding?

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