IB Chemistry on VSEPR

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IB Chemistry on VSEPR

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  • 1.http://lawrencekok.blogspot.com Prepared by Lawrence Kok Tutorial on VSEPR.

2. brown liquid yellow gas greenish gas violet solid Covalent bonding between non metals Gp 17 Non metalGp 17 Non metal Non metal High EN value Gain electron (anion) Electronegative ions Covalent Bond Group 17 Non metal High EN value Gain electron (anion) Electronegative ions 3. brown liquid yellow gas greenish gas violet solid Covalent bonding between non metals 2.8.7 Gp 17 Non metal achieve stable octet structure CI 2.8.8 2.8.7 Sharing electron Gp 17 Non metal 2.8.8 CI Non metal High EN value Gain electron (anion) Electronegative ions Covalent Bond Group 17 Non metal High EN value Gain electron (anion) Electronegative ions 4. brown liquid Click here simulation on covalent bond yellow gas greenish gas violet solid Covalent bonding between non metals 2.8.7 Gp 17 Non metal achieve stable octet structure CI shared pair electron Covalent Bonding Electrostatic forces attraction between nucleus with shared pair electron 2.8.8 2.8.7 Sharing electron Gp 17 Non metal 2.8.8 CI Non metal High EN value Gain electron (anion) Electronegative ions Covalent Bond Group 17 CICI Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron CI CI: x x :: :. x x X x x x x CI CI :: x x x x CI CI Non metal High EN value Gain electron (anion) Electronegative ions Single covalent bond shared pair electron 5. Bond length and Bond strength Bond length = 0.199nm Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron CI CI: x x :: : : . x x X X x x x x O CI CI:: x x x x x x CI CI O O: x x O N O O N: Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron : : . N N: N N Bond length = 0.121nm Bond length = 0.110nm 6. Bond Bond order Bond strength Bond length/pm C - C 1 347 154 C = C 2 612 134 C C 3 820 120 N - N 1 159 145 N = N 2 418 123 N N 3 914 110 Bond length and Bond strength Bond length = 0.199nm Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron CI CI: x x :: : : . x x X X x x x x O CI CI:: x x x x x x CI CI O O: x x O N O O N: Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron : : . N N: N N Triple bond > Double bond > Single bond Bond length decrease Bond strength Increase (Double/Triple bond) Bond length = 0.121nm Bond length = 0.110nm Bond order up Bond strength up Bond length down 7. Bond Bond order Bond strength Bond length/pm C - C 1 347 154 C = C 2 612 134 C C 3 820 120 N - N 1 159 145 N = N 2 418 123 N N 3 914 110 Bond length and Bond strength Bond length = 0.199nm Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron CI CI: x x :: : : . x x X X x x x x O CI CI:: x x x x x x CI CI O O: x x O N O O N: Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron O : : . N N: N N : Triple bond > Double bond > Single bond Bonding pair e -involve in bonding Bond length decrease Bond strength Increase (Double/Triple bond) Bond length = 0.121nm Bond length = 0.110nm Bond order up Bond strength up Bond length down O: Non bonding pair (Lone pair electron) Bonding pair electron C O: : Bonding pair electron Dative bond (electron pair of oxy) Types of bonding Lone pair e not involve in bonding Dative/coordinate bond - pair e come from an atom 8. : . CI .. x Bond Bond order Bond strength Bond length/pm C - C 1 347 154 C = C 2 612 134 C C 3 820 120 N - N 1 159 145 N = N 2 418 123 N N 3 914 110 Bond length and Bond strength Bond length = 0.199nm Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron CI CI: x x :: : : . x x X X x x x x O CI CI:: x x x x x x CI CI O O: x x O N O O N: Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron Lewis structure/diagram . Electron cross dot . Valence/bonding pair electron O : : . N N: N N : Triple bond > Double bond > Single bond Bonding pair e -involve in bonding Bond length decrease Bond strength Increase (Double/Triple bond) Bond length = 0.121nm Bond length = 0.110nm Bond order up Bond strength up Bond length down O: Non bonding pair (Lone pair electron) Bonding pair electron C O: : Bonding pair electron Dative bond (electron pair of oxy) Types of bonding Lone pair e not involve in bonding Dative/coordinate bond - pair e come from an atom Exception to octet rule All period 2 element - observe octet rule except Be and B Electron deficient Less than 8 valence e Expanded octet More than 8 valence e All period 3 element - observe octet rule except P and S : BeCI CIx . : :: :: x x. Be - 4 valence e BCI CI : :: : :: x : :B - 6 valence e P S CI CI CI CI CI CI CICI CICI CI P - 10 valence e S 12 valence e 9. Valence Shell Electron Pair Repulsion Predict molecular shape/geometry Shape determine by electron pairs/ electron charge centers/ECC Valence Shell Electron Pair Repulsion NOT surrounding atoms N H HH .. Shape of molecule Lewis structure VSEPR .. N H H H Shape 10. Valence Shell Electron Pair Repulsion Predict molecular shape/geometry Shape determine by electron pairs/ electron charge centers/ECC Bonding/lone pair repel each other Bonding/lone pair arrange themselves as far as possible (minimise repulsion) Valence Shell Electron Pair Repulsion NOT surrounding atoms N H HH .. Principles of VSEPR Shape of molecule Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC 3 4 Lone pair-lone pair > Lone pair-bonding pair > bonding pair-bonding pair repulsion 5 6 ECC or electron pair position in equatorial first, then axial Lewis structure VSEPR .. N H H H Shape 11. Valence Shell Electron Pair Repulsion Predict molecular shape/geometry Shape determine by electron pairs/ electron charge centers/ECC Bonding/lone pair repel each other Bonding/lone pair arrange themselves as far as possible (minimise repulsion) Valence Shell Electron Pair Repulsion NOT surrounding atoms N H HH .. Principles of VSEPR Shape of molecule Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC 3 4 Lone pair-lone pair > Lone pair-bonding pair > bonding pair-bonding pair repulsion 5 6 ECC or electron pair position in equatorial first, then axial Excellent VSEPR simulation Click here Click here VSEPR notes Lewis structure VSEPR .. N H H H Shape Click here VSEPR simulation 12. Valence Shell Electron Pair Repulsion Principles of VSEPR Determine number valence e around central atom1 .. N HHH 3 bonding pair 1 lone pair 4 ECC N central atom 13. Valence Shell Electron Pair Repulsion Principles of VSEPR Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC .. N HHH 3 bonding pair 1 lone pair 4 ECC N central atom 3 ECC C H =O H H C N 2 ECC OH H 4 ECC 14. Valence Shell Electron Pair Repulsion Principles of VSEPR Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC 3 Bonding/lone pair repel each other Lone /lone pair > Lone /bond pair > bond/bond pair repulsion .. N HHH 3 bonding pair 1 lone pair 4 ECC N central atom 3 ECC C H =O H H C N 2 ECC OH H 4 ECC > > 1 lone pair2 lone pair 0 lone pair Repulsion greater - Bond angle smaller Repulsion greater Repulsion greater 15. Valence Shell Electron Pair Repulsion Bonding/lone pair arrange themselves as far as possible (minimise repulsion) Principles of VSEPR Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC 3 Bonding/lone pair repel each other Lone /lone pair > Lone /bond pair > bond/bond pair repulsion 4 5 .. N HHH 3 bonding pair 1 lone pair 4 ECC N central atom 3 ECC C H =O H H C N 2 ECC OH H 4 ECC > > 1 lone pair2 lone pair 0 lone pair Repulsion greater - Bond angle smaller Repulsion greater Repulsion greater ECC far apart Bond angle greatest minimise repulsion Lone pair need more space Multiple bonds more space Unequal repulsionEqual repulsion 109.5 107 16. Valence Shell Electron Pair Repulsion Bonding/lone pair arrange themselves as far as possible (minimise repulsion) Principles of VSEPR Determine number valence e around central atom1 2 Single, double, triple bond , lone pair act as electron charge center/ECC 3 Bonding/lone pair repel each other Lone /lone pair > Lone /bond pair > bond/bond pair repulsion 4 5 For 5/6 ECC: ECC position in equatorial first, then axial .. N HHH 3 bonding pair 1 lone pair 4 ECC N central atom 3 ECC C H =O H H C N 2 ECC OH H 4 ECC > > 1 lone pair2 lone pair 0 lone pair Repulsion greater - Bond angle smaller Repulsion greater Repulsion greater ECC far apart Bond angle greatest minimise repulsion 6 Lone pair need more space Multiple bonds more space Unequal repulsionEqual repulsion 90 120 109.5 107 180 17. H Linear Bond angle - 180 O OO C BeH N X x O C H NO C OO CH N HH Be N OX x X X X X X X X x X x + + : CO2 HCN BeH2 NO2 +Lone Pair Bonding Pair Geometry 2 bond pair E L E C T R O N C E N T E R 18. H Linear Bond angle - 180 O OO C BeH N B X x C SO O C H NO C OO CH N HH Be N OX x X X X X X X X x X x + + : F F F H H O O O C O O O B X F F F C H H x x O S O O C O x x O 2- 2- O x x : || BF3 CH2 O SO3 CO3 2- CO2 HCN BeH2 NO2 +Lone Pair Bonding Pair Geometry 2 bond pair = = Geometry 3 bond pair Bond angle - 120 Trigonal planar E L E C T R O N C H A R G E C E N T E R E L E C T R O N C E N T E R 19. H Bond angle - 104.5 Linear Bond angle - 180 O OO C BeH N B X x C SO O C H NO C OO CH N HH Be N OX x X X X X X X X x X x + + : F F F H H O O O C O O O B X F F F C H H x x O S O O C O x x O 2- 2- O x x : || BF3 CH2 O SO3 CO3 2- CO2 HCN BeH2 NO2 +Lone Pair Bonding Pair Geometry 2 bond pair = = Geometry 3 bond pair Bond angle - 120 Trigonal planar E L E C T R O N C H A R G E C E N T E R O3 O O O : O O : O NO2 N OO N OO NO2 - N OO : N OO : SO2 OO - - S : S OO : Geometry 2 bond pair 1 lone pair Bent E L E C T R O N C E N T E R 20. Bond angle -104.5 : O HH H2O H H O O F2O F F F F O S CICI SCI2 N H H S CI CI N H NH2 - - - H: : : : : : : : : : : Bent Lone Pair Bonding Pair E L E C T R O N C H A R G E C E N T E R Geometry 2 bond pair 2 lone pair 21. Bond angle -104.5 O Bond angle- 107 Trigonal Pyrimidal N H N : : O SO3 2-PH3NH3 O HH H2O H H O O F2O F F F F O S CICI SCI2 N H H S CI CI N H NH2 - - - H: : : : : : : : : : : Bent CIO3 - H H P H H H H H H P H H H : O O S O S O : O 2- 2- CI O O O CI : O O - : : : : : Lone Pair Bonding Pair E L E C T R O N C H A R G E C E N T E R Geometry 2 bond pair 2 lone pair Geometry 3 bond pair 1 lone pair - 22. Bond angle -109.5 Bond angle -104.5 O Bond angle- 107 Tetrahedral Trigonal Pyrimidal N H N : : O SO3 2-PH3NH3 O HH H2O H H O O F2O F F F F O S CICI SCI2 N H H S CI CI N H NH2 - - - H: : : : : : : : : : : Bent CIO3 - H H P H H H H H H P H H H : O O S O S O : O 2- 2- CI O O O CI : O O - : CH4 C H NH4 + BH4 - PCI4 + H H H H C H H H N H H H H H N H H H H B HH H H B H H H CI CI CI CI P CI CI CI P CI - - + + + + :: : :: :: : : :: : : : : : Lone Pair Bonding Pair E L E C T R O N C H A R G E C E N T E R Geometry 2 bond pair 2 lone pair Geometry 3 bond pair 1 lone pair Geometry 4 bond pair - 23. Trigonal Bipyrimidal Bond angle - 90 , 120 P CI CI CI CI CI P CI CI CI CI CI PCI5Bonding Pair Lone Pair E L E C T R O N C H A R G E C E N T E R Geometry 5 bond pair 24. Bond angle