CHEMISTRY PROJECTMADE BYARHAM KHAN

ACKNOWLEDGEMENTI would like to express my greatest gratitude to the people who have helped & supported me throughout my project. I am grateful to my teacher Mrs.Anushka Sharmafor her continuous support for the project, from initial advice & contacts in the early stages of conceptual inception & through ongoing advice & encouragement to this day. A special thank of mine goes to my colleague who helped me in completing the project & she exchanged her interesting ideas, thoughts & made this project easy and accurate. I wish to thank my parents for their undivided support and interest who inspired me and encouraged me to go my own way, without whom I would be unable to complete my project. At last but not the least I want to thank my friends who appreciated me for my work and motivated me and finally to God who made all the things possible... ... ...

ATOMIC ORBITALS & COVALENT BONDING*ATOMIC ORBITALS ARE MATHEMATICAL DESCRIPTIONSOF THE probable locations of electrons aroundan atom.s, px, py, pz, dxy, dxz, dyz, dx2-y2, dz2, ...Atomic orbitals can be blended togetherto form new orbitals called hybrid orbitals.

SP ORBITAL HYBRIDIZATION*The shape is determinedby the linear combinationsof atomic orbitalsy2s + y2pzandy2s - y2pz

SP2 ORBITAL HYBRIDIZATION*2s=2pz2pxsp2The 2s, 2px and 2pz atomic orbitalsof each carbon are used.The angle between the orbitals is 120.

SP3 ORBITAL HYBRIDIZATION*

SP3 ORBITAL HYBRIDIZATION*four sp3 orbitalsThe angle between the orbitals is 109.5.Why isnt the angle 90?tetrahedral shape

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*sp3 Osp2 Nsp3 Nsp Csp2 Csp3 CPredict the bond angles and the hybridizationof the central atoms in each of the following structures.sp Be

BERYLLIUM SP HYBRIDIZATION*Two orbitalseach can hold two electrons

SP HYBRIDIZATION*px, pyhaoMaximum angle thattwo orbitals can beapart is 180.atomicorbtialshybrid atomicorbtials

SP HYBRIDIZED BERYLLIUMVALENCE ORBITALS*Open orbital contains no electronsLined orbital contains one electronFilled in orbital contains two electronsThe other p-orbitalsof beryllium (px, py)remain unchanged

SP HYBRIDIZED BERYLLIUMVALENCE ORBITALS*Open orbital contains no electronsLined orbital contains one electronFilled in orbital contains two electronsThe other p-orbitalsof beryllium (px, py)remain unchangedWhy is it a linear molecule?

*Sketch the hybrid atomic orbitals and fill orshade-in the lobes for each indicated atomsp2 Osp3 Osp2 Nsp3 Nsp Csp Nsp2 Csp3 C

*Sketch the hybrid atomic orbitals and fill orshade-in the lobes for each indicated atomsp2 Osp3 Osp2 Nsp3 Nsp Csp Nsp2 Csp3 C

ETHENEALSO CALLED ETHYLENEPOLYMERIZES TO FORM POLYETHYLENEEACH CARBON FORMS THREE SP2 HYBRID ORBITALS.*

SP2 HYBRIDIZATION*haoThe unhybridized py orbital isperpendicular to the sp2 orbitals.2pyThis hybrid setcan hold six electrons.

ETHENETO ALLOW FOR OVERLAP OF THE UNHYBRIDIZED PY ORBITALS, THE BONDING IN THIS MOLECULE REQUIRES THAT ETHENE IS PLANAR. ALL SIX ATOMS LIE IN THE SAME PLANE.*

ETHENE*carbon-carbon sigma bonddue to sp2-sp2 overlapcarbon-carbon pi bonddue to 2py- 2py overlapcarbon-hydrogensigma bondsdue to sp2-s overlap

METHANE*The 2s, 2px , 2py and 2pz atomic orbitalsof carbon are used.What would be the name of a hybrid orbitalmade from these orbitals?

SP3 HYBRIDIZATION*sp3All four hybridatomic orbitalshave the sameenergy.These four orbitals areenergetically degenerate.

METHANE*

AMMONIA*NHHHThe 2s, 2px , 2py and 2pz atomic orbitals of nitrogenare used

SP3 HYBRIDIZATION*sp3nitrogenaohaoBy hybridizing itsatomic orbitalsnitrogen gainsmore stable(lower energy)orbitals for bonding.Which of the electrons in thesehybrid atomic orbitals are available for bonding?

AMMONIA*a completely filled inorbital containstwo electronsBecause of this bonding,the H-N-H bond angleis close to 109.5 (actually 107).

HYDROGEN CYANIDE*carbonsp hybridizedHow many electronsare in each orbital?nitrogensp hybridizedHow many electronsare in each orbital?hydrogen1s orbital

HYDROGEN CYANIDE*

HYDROGEN CYANIDE*(between hydrogen and carbonand carbon and nitrogen)(between carbonand nitrogen)

NITRITE ION*3 groups of electrons around nitrogen O-N-O @ 120Why is the bond angleapproximately 120?Draw the hybridizedatomic orbitalsfor each atomO1 sp2 hybridizedO2 sp3 hybridized

NITRITE ION1s2 2s2 2p41s2 2s2 2p31s2 2s2 2p4-1 charge

NITRITE ION*How would the bonding changeif O2 was unhybridized?

ETHENE*3 groups of electrons around carbon C-C-H @ 120 H-C-H @ 120

ETHANE*4 groups of electrons around carbon C-C-H @ 109.5 H-C-H @ 109.5

DIPOLE MOMENTSCHARGE IS NOT ALWAYS EQUALLY DISTRIBUTED IN A MOLECULE.*There can be a region of positive charge and of negative charge.The vector connecting these regions is called the dipole moment.

PREDICTIONSFOR MOLECULAR COMPOUNDSSOLUBILITY AND MISCIBILITY ARE RELATED TO THE POLARITY (I.E., DIPOLE MOMENT) OF THE MOLECULE.*"Like dissolves like" is a rule of thumb for solubilitypolar molecules dissolve in polar solventsnonpolar molecules dissolve in nonpolar solvents

CARBONATE ION*The concept of dipole momentscan also be applied to ions,although they generallydissolve in polar solvents(e.g., water) becauseof their charge.Although carbonate ionhas no net dipole moment,it dissolves in polar solventsbecause of its ionic charge.

LIKE DISSOLVES LIKETHE RULE "LIKE DISSOLVES LIKE" IS NOT PERFECT;HOWEVER, IT DOES SERVE AS A STARTING POINT IN DETERMINING WHAT TYPE OF SOLVENT TO USE WHEN ATTEMPTING TO DISSOLVE A SOLID.*

POLARITY PREDICTIONSRANK THE FOLLOWING MOLECULES IN TERMS OF POLARITY:WATER, BENZENE, CHLOROFORM*