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Sunday, December 27, 2020

Does 2s and 2p have the same energy?

'NO' the energy of atomic orbitals depends upon principal as well as azimuthal quantum number, which is  more common known as (n+l) rule .
According to (n+l) rule the atomic orbital has less (n+l)  value also has less energy vice versa.
For 2S => n= 2, l=0,. =>n+l= 2+0=2
For 2p => n= 2, l=2,. =>n+l= 2+1=3
Hence 2p have more energy than 2s orbital

Saturday, December 26, 2020

Which orbital has much overlap capacity?

When internuclear distance is fixed then overlapping extent of atomic orbitals depends on directional nature of orbitals. And higher the directional nature of orbitals more stronger will be extent of overlapping and more stronger bond will form
Order of extent of over lapping given as:
          2p-2p > 2s-2p > 2s-2s

Why the extent of overlap is more in 2p-3d than 2p-3p?

The order of overlapping strength of orbitals is given as:

2pπ-2pπ>2pπ-3dπ>2pπ-3pπ>3pπ-3pπ.
The strength of π-bond is directly proportional to the overlapping strength of orbitals because on greater overlapping distance between two nuclei decreases and bond strength increase hence order of π-bond also given as:

2pπ-2pπ>2pπ-3dπ>2pπ-3pπ>3pπ-3pπ.

2pπ-2pπ, π-bonding is stronger than 2pπ-3dπ, π-bonding due to the lower energy gap (n=2) between them.
The importance comparison is in between 2pπ-3dπ and 2pπ-3pπ. The overlapping strength of 2pπ-3dπ  is more than 2pπ-3pπ this is due to fact that , the 3d orbitals have two lobes which are more bent than 3p orbitals. That why overlapping strength increase.

Friday, December 25, 2020

How to determine order of bond angle of Me-O-Me, H3Si-O-SiH3 and (ph)3Si-O-Si(Ph) ?

 (1) Oxygen of Me-O-Me is sp3 hybridised so C-O-C bond angle is more than 109’28” approx 110” due to crowding of methyl group.

(2) In disilyl ether , oxygen is Sp2 hybridised and planer due to back bonding between oxygen and silicon atom.  In this back bonding lone pair of oxygen atom donate to the vacant d orbital of silicon atom  due to this fact bond lengths of Si-O is decrease and  increases (approx 140”).

(3) In (Ph)3Si-O-Si(Ph)3  compounds Si-O-Si bond angle is Approx 180 due to back bonding and hybridisation is Sp.


Related Questions:

Why trimethylamine amine ( N(CH3)3) is tetrahedral while trisilyl amine (N(SiH3)3) planner.?









How to compared bond angle (C-N-C) and (Si-N-Si) in trimethyl amine and trisilyl amine respectively?

Nitrogen (N) atom in trimethyl amine [N(CH3)3] is sp3 hybridised and tetrahedral ( bond angle ~107)  due to non bonding electron pair of N is localised (more basic). On the other hand N atom of trisilyl amine [N(SiH3)3] is sp2 hybridised and trigonal planner (bond angle~120).This is due to the participation of non-bondlng pair of N into pπ-dπ back banding. Due to this delocalization of non-bonding electron pair of N in trisilyl amine it is also less basic

Related Questions:

Why trimethylamine amine ( N(CH3)3) is tetrahedral while trisilyl amine (N(SiH3)3) planner.?









What is structure (CF3)2-Al-O-Al-(CF3)2 and also find the number of pi bond or Back bond?