1. ORGANIC MECHNISMS

2. MEET THE ATTACKERS Press the space bar

3. MEET THE ATTACKERS I AM A NUCLEOPHILE I HAVE A LONE PAIR WHICH I CAN USE TO FORM A NEW BOND. I ATTACK ELECTRON DEFICIENT AREAS (those with a + or  )

4. MEET THE ATTACKERS Press the space bar

5. MEET THE ATTACKERS I AM AN ELECTROPHILE I HAVE A + CHARGE or a  CHARGE. I ATTACK ELECTRON RICH AREAS SUCH AS C=C DOUBLE BONDS.

6. MEET THE ATTACKERS Press the space bar

7. MEET THE ATTACKERS AND I AM A FREE RADICAL I HAVE AN UNPAIRED ELECTRON WHICH I WANT TO PAIR UP. I AM VERY REACTIVE AND DON’T MIND WHERE I ATTACK… WATCH OUT!

8. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT WHO IS ATTACKED?

9. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE A typical covalent bond with one shared pair – nothing to tempt an attacking species WHO IS ATTACKED?

10. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted WHO IS ATTACKED?

11. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond WHO IS ATTACKED?

12. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond Atoms have different electronegativities and the shared pair will be attracted more to one end – species known as nucleophiles will be attracted to the slightly positive end WHO IS ATTACKED? 

13. THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond Atoms have different electronegativities and the shared pair will be attracted more to one end – species known as nucleophiles will be attracted to the slightly positive end WHO IS ATTACKED? 

14. ALKANES ARE RELATIVELY UNREACTIVE ORGANIC COMPOUNDS ALKANES CONTAIN TWO BOND TYPES C-H and C-C WHAT ATTACKS ALKANES? Both bonds are single – no electron rich areas Bonds are non-polar - no electron deficient areas Free radicals are very reactive and do attack FREE RADICAL SUBSTITUTION

15. ALKENES ARE MUCH MORE REACTIVE THAN ALKANES ALKENES CONTAIN A C=C BOND There will be twice as many electrons between the carbon atoms as there are in a single bond WHAT ATTACKS ALKENES? C=C bond is double – an electron rich area Bonds are non-polar - no electron deficient areas ELECTROPHILIC ADDITION

16. HALOGENOALKANES ARE MUCH MORE REACTIVE THAN ALKANES HALOGENOALKANES CONTAIN A POLAR BOND The halogen is more electronegative than the carbon attracts the shared electron pair. WHAT ATTACKS HALOGENOALKENES? Bond is single – not an electron rich area Bond is polar – the greater electronegativity of the halogen creates a dipole making the carbon atom electron deficient.  NUCLEOPHILIC SUBSTITUTION

17. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS CURLY ARROWS

18. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS CURLY ARROWS ELECTRONS MOVE FROM AREAS OF HIGH ELECTRON DENSITY TO ONES WITH A LOWER ELECTRON DENSITY

19. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS CURLY ARROWS ELECTRONS MOVE FROM AREAS OF HIGH ELECTRON DENSITY TO ONES WITH A LOWER ELECTRON DENSITY For example… from LONE PAIRS DOUBLE BONDS

20. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS CURLY ARROWS ELECTRONS MOVE FROM AREAS OF HIGH ELECTRON DENSITY TO ONES WITH A LOWER ELECTRON DENSITY For example… from LONE PAIRS DOUBLE BONDS toPOSITIVE SPECIES THE  END OF POLAR BONDS

21. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS CURLY ARROWS

22. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS ARROWS WITH TWO ‘HEADS’ INDICATE THE MOVEMENT OF TWO (A PAIR OF) ELECTRONS CURLY ARROWS

23. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS ARROWS WITH TWO ‘HEADS’ INDICATE THE MOVEMENT OF TWO (A PAIR OF) ELECTRONS CURLY ARROWS A PAIR of electrons moves from here… to here

24. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS ARROWS WITH TWO ‘HEADS’ INDICATE THE MOVEMENT OF TWO (A PAIR OF) ELECTRONS CURLY ARROWS A PAIR of electrons moves from here… to here ARROWS WITH ONE ‘HEAD’ INDICATE THE MOVEMENT OF JUST ONE ELECTRON

25. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS ARROWS WITH TWO ‘HEADS’ INDICATE THE MOVEMENT OF TWO (A PAIR OF) ELECTRONS CURLY ARROWS A PAIR of electrons moves from here… to here ARROWS WITH ONE ‘HEAD’ INDICATE THE MOVEMENT OF JUST ONE ELECTRON ONE electron moves from here… to here

26. THESE ARE USED TO REPRESENT THE MOVEMENT OF ELECTRONS ARROWS WITH TWO ‘HEADS’ INDICATE THE MOVEMENT OF TWO (A PAIR OF) ELECTRONS CURLY ARROWS A PAIR of electrons moves from here… to here ALWAYS BE PRECISE WITH THE POSITIONING OF ANY ARROWS ARROWS WITH ONE ‘HEAD’ INDICATE THE MOVEMENT OF JUST ONE ELECTRON ONE electron moves from here… to here

27. NUCLEOPHILES:- possess a lone pair of electrons DRAWING CURLY ARROWS

28. NUCLEOPHILES:- possess a lone pair of electrons DRAWING CURLY ARROWS HYDROXIDE ION negative charge H O lone pair more lone pairs

29. NUCLEOPHILES:- possess a lone pair of electrons DRAWING CURLY ARROWS HYDROXIDE ION negative charge H O lone pair more lone pairs AMMONIA MOLECULE Nucleophiles don’t need to have negative charge… BUT they must have a lone pair lone pair H H N H

30. NUCLEOPHILES:- possess a lone pair of electrons DRAWING CURLY ARROWS HYDROXIDE ION negative charge H O lone pair more lone pairs AMMONIA MOLECULE Nucleophiles don’t need to have negative charge… BUT they must have a lone pair lone pair H H N H

31. ELECTROPHILES:- attract a lone pair of electrons DRAWING CURLY ARROWS

32. ELECTROPHILES:- attract a lone pair of electrons DRAWING CURLY ARROWS HYDROGEN ION H There are no electrons in the outer shell of hydrogen so it has space to accept two electrons

33. ELECTROPHILES:- attract a lone pair of electrons DRAWING CURLY ARROWS HYDROGEN ION H There are no electrons in the outer shell of hydrogen so it has space to accept two electrons HYDROGEN CHLORIDE contains a POLAR BOND; the  end will attract the electron pair H C l 

34. ELECTROPHILES:- attract a lone pair of electrons DRAWING CURLY ARROWS HYDROGEN ION H There are no electrons in the outer shell of hydrogen so it has space to accept two electrons HYDROGEN CHLORIDE contains a POLAR BOND; the  end will attract the electron pair H C l 

35. DRAWING CURLY ARROWS When moving electrons about, it is essential to check that the charges on the reactants and products balance. ‘BALANCING THE BOOKS’ H O H C C Br H 3 H H C C O H H 3 H Br  This is the basic mechanism for the nucleophilic substitution of bromoethane.

36. DRAWING CURLY ARROWS When moving electrons about, it is essential to check that the charges on the reactants and products balance. ‘BALANCING THE BOOKS’ H O H C C Br H 3 H H C C O H H 3 H Br  This is the basic mechanism for the nucleophilic substitution of bromoethane. To see how it works, it helps to show the electrons involved.

37. DRAWING CURLY ARROWS When moving electrons about, it is essential to check that the charges on the reactants and products balance. ‘BALANCING THE BOOKS’ H O H C C Br H 3 H H C C O H H 3 H Br

38. DRAWING CURLY ARROWS When moving electrons about, it is essential to check that the charges on the reactants and products balance. ‘BALANCING THE BOOKS’ H O The hydroxide ion has a – ive charge, The oxygen has eight electrons in its outer shell. Because it has a lone pair, the ion will act as a nucleophile

39. DRAWING CURLY ARROWS When moving electrons about, it is essential to check that the charges on the reactants and products balance. ‘BALANCING THE BOOKS’ H O H C C Br H 3 H In bromoethane, C 2 H 5 Br, the C-Br bond is polar because the electronegativity of Br is greater than C. It will susceptible to attack by nucleophiles. 

40.  In addition reactions, 2 or more substances react to form a single product only ADDITION REACTIONS C 2 H 4 (g) + Br 2 (l) ——> CH 2 BrCH 2 Br(l) ethene 1,2 - dibromoethane Reactant 1 + Reactant 2  Product Example : Bromine undergoes addition reaction with ethene Reactant  Product 1 + Product 2 ELIMINATION REACTIONS  It is opposite of addition reaction. One substance react to form 2 products C 3 CH 2 OH ————> CH 2 =CH 2 + H 2 O ethenol ethene Example :Dehydration of ethenol

41. CONDENSATION REACTION  Involves addition reaction followed by an elimination reaction  Two reactants combine to form a larger molecule with the elimination of a small molecule like water CH 3 CH 2 OH (l) + CH 3 COOH (l) CH 3 COOC 2 H 5 (l) + H 2 O (l) ethanol ethanoic acid ethyl ethanoate + water Example : formation of ester from carboxylic acid SUBSTITUTION REACTION  One atom or group of atoms replaced by another atom or group of atoms Reactant 1 + Reactant 2  Product 1 + Product 2

42. OXIDATION AND REDUCTION  reactions when oxidation or deduction takes place Example : oxidation of primary alcohol to form aldehyde HYDROLYSIS  Splitting up a molecule by reacting with water CH 3 CH 2 Br + H 2 O  CH 3 CH 2 OH + HBr Example :hydrolysing of bromoethane Note [O] means oxidising agent

43. POLYMERISATION  Joining of small (monomers) together in to a long chain  2 types of polymerization are there. They are Adition polymerisation and condensation polymerization Polymer could be represented by : -[M] n -

44. There are 3 ways to split the shared electron pair in an unsymmetrical covalent bond. UNEQUAL SPLITTING produces: IONS (negative ions are called Carbanion. Positive ions are called Carbocation) known as HETEROLYTIC FISSION EQUAL SPLITTING produces RADICALS known as HOMOLYTIC FISSION If several bonds are present the weakest bond is usually broken first Energy to break bonds can come from a variety of energy sources - heat / light In the reaction between methane and chlorine either can be used, however... In the laboratory a source of UV light (or sunlight) is favoured. HOMOLYTIC AND HETROLYTIC FISSION

45. The formation of a carbocation from a halogenoalkane is an example of ?? heterolytic fission.

46. Free radical – species with an unpaired electron Electrophile – species that accepts a pair of electrons which are attracted to region of higher electron density Nucleophile – species that donates a pair of electrons which attacks region of lower electron density