A very simple doubt from Chemical Bonding

[Arush_Sharma]

The given answer is Square Pyramid but it should be Octahedral according to me.
My doubt is that since they have asked the "Geometry" (not shape), so don't we take the lone pair into account? imo that's the only difference in betweem shape and Geometry and as far as I remember I have studied this in class.
The bigger problem is that it is a previous year JEE Main question and the answer in the final answer key of that year says square pyramid.
[JEE Main Online 10th April 2015]
@Gurnoor_Singh @Chirag_Hegde @pratyaksh_tyagi

[seshu_ram]

Yes 5 bp 1 lp. You know the trick to find lp and bp?

[seshu_ram]

Shape is octahedral and geometry square pyramidal

[seshu_ram]

See what you basically need is 6 electron pairs for the shape to be octahedral. This can be achieved by 5 bp+1lp (square pyramidal) or 4 bp+2lp (square planar). I’ll find a PDF that will be very helpful for you to do such questions gimme some time.

Handout_Lewis_VSEPR.pdf

As for the trick.

Add valence electrons of all atoms except H. Now multiply number of H atoms by 7 and add this number to the above obtained sum. Divide the final sum obtained by 8. Quotient gives bp and remainder when divided by 2 gives lp. Please note that this does not work for molecules with two central atoms.

[Arush_Sharma]

Thanks for the effort
But isn't shape Square Pyramid and Geometry Octahedral? Or am I forgetting something very basic?

What I am saying is this. (But I know that quora isn't reliable still I too support that whatvis in the screenshot

[Sourav_Kumar]

Yes. Shape is sq pyramidal and geometry octahedral
I think he mistyped

[seshu_ram]

Bro refer to that document it’s really nice. I think it will clarify your doubt. Did you watch this YouTube video by any chance

[Arush_Sharma]

No I did not watch that Video. Thanks for your concern. But I still don't think that we count lp in shape.
And bro @seshu_ram your pdf also says that 5BP +1LP is square planar SHAPE but the question asks "Geometry"

[seshu_ram]

Sahi hai bhai I mistyped @sourav_kumar
Sorry for inconvenience @Arush_Sharma

I typed just the opposite I meant what you’ve said in the above post. Yes but how can mains key be wrong? Did u check official key?

[Arush_Sharma]

Oh great👍
What about the answer then?

[seshu_ram]

Your answer is correct shape : Square pyramidal
Geometry: Octahedral

[Sourav_Kumar]

Honestly the question is ambiguos as they have not cleared the term 'geometry'
Geometry can be electronic or molecular. They should have specified that. But ncert does not differentiate anywhere between these. They don't talk about electronic geometry. According to that shape and geometry are same things (both are molecular geometry that is) and so ans could be given sq pyramidal as you know.. Ncert is god. Just see pg 111 of ncert 11th "shape(geometry)" written which implies both are same.

This is Messed up.

[seshu_ram]

Bhai whether NCERT mentions it or not JD Lee does. Believe the Bible.

[Sourav_Kumar]

Doesn't matter in jee bro

Ncert=Omnipotent

[seshu_ram]

It’s just very coincidental that this question didn’t make its way to the FIITJEE archive

[Arush_Sharma]

Awesome guys. This is veerrry messed up then. And it was not even mentioned as grace that year( when 3 questions in physics were given as grace) Thanks Sourav for pointing out that NCERT shape(geometry) thing.
So I guess nothing can be done now.

One thing, if the same question comes in JEE, what should we do? (As we can reason both things )

And @seshu_ram FIITJEE archive has Online Questions of only Years 2013 and 14.The rest are only offline

[seshu_ram]

Mark what is correct. See yaar for every author of any inorganic book after 1980s... JD Lee is their reference.

Mine has 15. I guess coz mine is updated.

[Yash_Srivastava2]

many times what ans given in ncert is taken into consideration even if its wrong it had happened many times ncert and other books clashed
but only ncert won

[seshu_ram]

Yes let them play with the students lives coz of their lack of knowledge (CBSE ehh). God knows how many times mains got leaked as well... you never know. It’s just disgusting to note that people who are right don’t get marks. A ‘-1’ over a ‘+4’ imo a really wrong thing to do. This is not boards, this is JEE.

[Yash_Srivastava2]

I asked my sir and look what he said
There are mainly two term one is electronic geometry ,which is calculated by directly steric no.
Term geometry(shape) or molecular geometry(shape) refer for actual appearance without considering lone pairs...
if molecules don't have any lone pairs in that case electronic geometry and molecular geometry (shape) both are same
But if molecules have lone then electronic geometry and molecular geometry (shape) are different...
Conclusion is that Geometry or molecular geometry and shape both are same term..
generally in case of lone pairs we are using term shape..
In case of without lone pairs we are using term Geometry ...but both are same...
Different term is Electronic geometry and Geometry (molecular geometry or shape)