Homework Help: How to calculate protons and electrons in NH3BF3?

1. Dec 6, 2017

Indranil

I understand the concept of NH4+ ion but Still, I am confused. Please help me to understand the concept.
Could you tell me from your explanations: 1. could you explain what exotic condition is?
2. how does the nitrogen atom get some small positive charge? Thanking you

2. Dec 6, 2017

Staff: Mentor

Exotic conditions - for example we keep the ion in gaseous state, separated from others. It is not like these are defined in any way, it is just something that is very rare and not something you deal with on a daily basis (so if something needs exotic conditions to exist, you can safely assume it doesn't exist in typical conditions).

Why we observe partial charges I have explained earlier in the thread.

3. Dec 6, 2017

Indranil

Not sure what you are doing here. ±ve is (in the context of molecules and dipoles present on them) usually used to describe partial charges, not full charges. Electron is missing not because of "+ve", but because neutral ammonia accepted a single proton into its lone pair, no electrons moved together with this proton.

From your explanations above. I have doubts below:
1. What do you mean by 'dipole'? a dipole moment?
2. you said that there is small positive charge around Nitrogen due to partial charge. But as we know that 'N' is more electronegative than 'B' so the positive charge should be around 'B' like in OH, there is a positive charge around 'H' and negative charge around 'O' because 'O' is more electronegative than 'H".
3. From where 'N' gets single proton here?
Could you clarify these points, please? I am confused about these points.

4. Dec 6, 2017

Staff: Mentor

Why don't you google for the definition?

You can't ignore electronegativity of three fluorine atoms, they pull electrons in their direction through the B atom.

It doesn't get this proton "here". Ammonia gets protonated in water solutions by water, or by acids present. NH4+ got into discussion because you were all the time referring to non existing NH3+, which looks like a common mistyping of a common ion NH4+.

5. Dec 7, 2017

Indranil

1. Could I consider 'dipoles' and 'partial charge' the same thing?
2. Could you tell me, in Al2Cl6 if we look at the structure, two molecules joined together using lone pairs on chlorine atoms to Aluminium by the coordinate bond. I marked the first molecule to be 1 and the second one to be 2. Now my question is that how does Cl of the 1st molecule give the lone pair of electrons to Al of the 2nd molecule and the vice-versa because the chlorine is more electronegative than aluminum?

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6. Dec 8, 2017

Staff: Mentor

No. Charge is charge (being "partial" doesn't change it into something else). Dipole requires two separated charges, not one.

Electronegativity doesn't matter here. It will help you predict electrons are in general closer to the chlorine atoms, but it doesn't stop electrons from being shared.

7. Dec 8, 2017

Indranil

1. Is It correct if I say two chlorine atoms attached apply force on aluminum to receive the pair of electrons?
2. could you explain the point 'it doesn't stop electrons from being shared' because I only knew that more electronegative elements tend to attract electrons from less electronegative elements.?