Hybrid OrbitalsHybrid Orbitals

polyatomic moleculespolyatomic molecules The number of bonds formedThe number of bonds formed Their geometriesTheir geometries

spsp Hybrid OrbitalsHybrid Orbitals Example BeF2 Example BeF2 Lewis structureLewis structure The VSEPR model predicts this structure The VSEPR model predicts this structure

will be linearwill be linear What would What would valence bond theoryvalence bond theory predict predict

about the structure? about the structure?

Electron configurationElectron configuration 99FF 11ss2222ss2222pp55

44Be Be 1 1ss2222ss2 2

twotwo unpaired electrons unpaired electrons

unpaired electron in a 2p orbital

In the ground state ,there are no unpaired electrons

obtain an unpaired electron by promoting an electron from the 2s orbital to the 2p orbital

Be atom can form two covalent bonds with F atoms

The structure of BeF2 is linear and the bond lengths are identical

We canWe can combine 2combine 2ss and 2and 2pp orbitals orbitals to produce a to produce a "hybrid""hybrid" orbital orbital ((spsp ((

The orbital diagram for this hybridization

NoteNote When orbitals are mixed (hybridized) When orbitals are mixed (hybridized)

الناتجة المهجنه المدرات عدد يكون المدارات اوخلط مزج الناتجة عند المهجنه المدرات عدد يكون المدارات اوخلط مزج عندالتهجين في الداخلة المدارت لعدد التهجين مساوي في الداخلة المدارت لعدد مساوي

The number of hybrid orbitals produced The number of hybrid orbitals produced is is equal to the sum of the orbitals being equal to the sum of the orbitals being hybridizedhybridized

hybrid orbital is identical hybrid orbital is identical except that they are except that they are oriented in different directionsoriented in different directions

مختلفة اتجاهات في وموجهه متطابقة تكون المهجنة مختلفة المدرات اتجاهات في وموجهه متطابقة تكون المهجنة المدرات

spsp22 andand spsp 3 3 Hybrid Hybrid OrbitalsOrbitals

BFBF33

Electron configurationElectron configuration 99FF 11ss2222ss2222pp55

55B B 1 1ss2222ss2 2 22pp1 1

threethree unpaired electrons unpaired electrons مدارات من التكافؤ غالف في منفردة الكترونات مدارات ثالث من التكافؤ غالف في منفردة الكترونات ثالث

مختلفهمختلفه three three spsp22 hybrid orbitals have a trigonal planar hybrid orbitals have a trigonal planar

arrangement to minimize electron repulsionarrangement to minimize electron repulsion نوع من مهجنه مدارات ثلاث نوع تنتج من مهجنه مدارات ثلاث التنافر spsp22 تنتج لتقليل مستوي مثلث شكل التنافر تتخذ لتقليل مستوي مثلث شكل تتخذ الال2كترونيالال2كتروني

trigonal planartrigonal planar

We can also mix with all We can also mix with all 33pp orbitals in the orbitals in the same subshellsame subshell

Example CHExample CH44 66C C 11ss2222ss2 2 22pp2 2

hybridizationFour atomic orbitals (2s + 3 × 2p) mix to formfour hybrid orbitals (4 × sp3)

HH22OO 88 O O 11ss2222ss2 2 22pp44

Hybridization InvolvingHybridization Involving dd OrbitalsOrbitals PFPF55 1515P P 11ss2222ss2 2 22pp6 6 33ss2233pp333d3d

Similarly hybridizing one s, three p and two d orbitals produce six identical hybrid sp3d2 orbitals in an octahedral geometry

hybridizing one s, three p and one d orbitals produce five identical hybrid sp3d orbitals

NHNH3 3 77N N 11ss2222ss2 2 22pp33

Lewis structureLewis structure VSEPRVSEPR indicates indicates tetrahedral geometrytetrahedral geometry

with one non-bonding pair of electrons with one non-bonding pair of electrons ((trigonal pyramidaltrigonal pyramidal ) )

Tetrahedral arrangement indicates Tetrahedral arrangement indicates four equivalent electron orbitals four equivalent electron orbitals

Valence Valence Electron Pair Electron Pair

GeometryGeometry

Number of Number of OrbitalsOrbitals

Hybrid Hybrid OrbitalsOrbitals

LinearLinear22spsp

Trigonal Trigonal PlanarPlanar

33spsp22

TetrahedralTetrahedral44spsp33

Trigonal Trigonal BipyramidalBipyramidal

55SpSp33dd

OctahedralOctahedral66SpSp33dd22

Multiple BondsMultiple Bonds

Bond Types σ-bond results from s-s s-p

p-p π-bond results from overlap two p-orbitals

Why double bonds occur frequently with

C, N, and O but not with larger molecules

Ethylene 66C 1C 1ss2222ss22 2 2pp22

These p-orbitals can overlap, sideways:π-bond

Delocalized OrbitalsMolecules with two or more resonance structures can have π-bond that extend over more than two bonded atoms .Electron on π-bond that extend over more two atoms are said to be delocalized

Home workHome work

Draw sketches illustrating the overlap between the Draw sketches illustrating the overlap between the following orbitals on two atomsfollowing orbitals on two atoms

1.1. 2s orbital on each 2s orbital on each

2.2. 2p2pzz orbital on each( assume that the atoms are on the z orbital on each( assume that the atoms are on the z axis )axis )

3.3. The 2s orbital on one and 2pThe 2s orbital on one and 2pzz orbital on the other orbital on the other Indicate the hybrid orbital set used by the central Indicate the hybrid orbital set used by the central

atom in each of the following molecules and ions atom in each of the following molecules and ions

BHBH44-- , NH , NH33, XeF, XeF22, BI, BI33 , PF , PF66

--

What set of hybrid orbitals is used by central atom in What set of hybrid orbitals is used by central atom in each of the following molecules and ions each of the following molecules and ions

HH33OO++ , CS , CS22 , SO , SO442-2-, I, I33

-- , XeF , XeF4 4

Determine the hybrid orbitals on the nitrogen in angle 1 and the C in angle 2.