Vsepr theory & hybridization

Made by:-

Sauhard Singhal

The shape of the molecule is determined by repulsions between all of the electron present in the valance shell.Electron pairs in the valence shell of the central atom repel each other and align themselves to minimize this repulsion.Lone pair electrons takes up more space round the central atom than a bondpair.Lone pair attracted to one nucleus, but bond pair is shared by two nuclei.The minimum repulsions to the state minimum energy and maximum stability of the molecule.

Lone pair -Lone pair Lone pair -Bond pair Bond

pair-Bond pair

Triple bond >double bond >single bond

Presence of lone pairs on the central atom causes slight distortion of the bond angles from the ideal shape.

The magnitude of repulsions between bonding pairs of electrons depends on the electronegativity difference between the central atom &the other atoms .

Determine the central atom.

Draw the electron dot structure and bar diagram

Find arrangement of electron pairs.

Find arrangement of bonding pairs.

Determine the geometry based on of bonding pairs.

BONDED PAIRS OF ELECTRONS ONLY

There are two electron pairs in the valance shell of Beryllium. [1s2 2s2 ]

Molecular geometry-Linear arrangement

H HBe

Three electron pairs in the valance shell of Boron. [1s2 2s2 2p1 ]

Molecular geometry- Trigonal Planar arrangement

BF

F

F

BONDED PAIRS AS WELL AS LONE PAIRS OF ELECTRONS

Molecular geometry- V-Shaped or Bent shape Electron pairarrangement- TetrahetralRepulsions between Lonepair- Lonepair ,Lonepair -Bondpair is possible.It causes slight distortion from 109⁰28′ to

104⁰27′

102⁰30′

It fails to predict the shapes of isoelectronicspecies[CH4&NH4

+] and transition metal compounds.

This model does not take relative sizes of substituents .

Unable to explain atomic orbitals overlap.

Concise Inorganic chemistry-J.D.LEE[Fifth edition]-Black well publishing.

Chemistry-Raymond chang.

Pictures from Wikipedia- free encyclopedia-www. Wikipedia.org.

Pictures from Google Images.

Thanks to my Teachers & friends

The intermixing of two or more pure atomicorbital's of an atom with almost same energy togive same number of identical and degeneratenew type of orbital's is known as hybridization.

The new orbital's formed are also known ashybrid orbital's.

During hybridization, the atomic orbital's withdifferent characteristics are mixed with eachother.

sp

sp2

sp3

sp3d

sp3d2

sp3d3

Intermixing of one 's' and one 'p'orbital's of almost equal energyto give two identical anddegenerate hybrid orbital's iscalled 'sp' hybridization.

These sp-hybrid orbital's arearranged linearly at by making180 ⁰ of angle.

They possess 50% 's' and 50% 'p'character.

Intermixing of one 's' and two'p' orbital's of almost equalenergy to give three identicaland degenerate hybrid orbital'sis known as sp2 hybridization.

The three sp2 hybrid orbital'sare oriented in trigonal planarsymmetry at angles of 120 ⁰ toeach other.

The sp2 hybrid orbital's have33.3% 's' character and 66.6%'p' character.

In sp3 hybridization, one 's'and three 'p' orbital's of almostequal energy intermix to givefour identical and degeneratehybrid orbital's.

These four sp3 hybrid orbital'sare oriented in tetrahedralsymmetry with 109 ⁰ 28' anglewith each other.

The sp3 hybrid orbital's have25% ‘s’ character and 75% 'p'character.

In sp3d hybridization, one 's', three 'p'and one 'd' orbital's of almost equalenergy intermix to give five identical anddegenerate hybrid orbital's, which arearranged in trigonal bipyramidalsymmetry.

Among them, three are arranged intrigonal plane and the remaining twoorbital's are present above and below thetrigonal plane at right angles.

The sp3d hybrid orbital's have 20% 's',60% 'p' and 20% 'd' characters.

Intermixing of one 's', three 'p' and two'd' orbital's of almost same energy bygiving six identical and degeneratehybrid orbital's is called sp3d2hybridization.

These six sp3d2 orbital's are arranged inoctahedral symmetry by making 90 ⁰angles to each other. This arrangementcan be visualized as four orbital'sarranged in a square plane and theremaining two are oriented above andbelow this plane perpendicularly.

In sp3d3 hybridization, one 's', three 'p'and three 'd' orbital's of almost sameenergy intermix to give seven sp3d3hybrid orbital's, which are oriented inpentagonal bipyramidal symmetry.

Five among the sp3d3 orbital's arearranged in a pentagonal plane bymaking 72⁰ of angles. The remaining arearranged perpendicularly above andbelow this pentagonal plane.

e PairHybridizatio

nShape

2 sp linear

3 sp2 trigonal planar

4 sp3 tetrahedral, pyramidal, or bent

5 sp3dtrigonal bipyramidal,

trigonal planar, or linear

6 sp3d2 octahedral, square planar, or linear

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