electrophile and nucleophile

Question 1

what is a nucleophile?

Answer 1

a species that has excess electron density such as a negatively charged species or one that has lone pair

Question 2

what is a electrophile?

Answer 2

a species that is electron deficient such as a positively charged species

Question 3

what does an electrophile want?

Answer 3

an electrophile wants electrons

Question 4

what does a nucleophile want?

Answer 4

a nucleophile wants to get rid of its electron therefore donates an electron to an electrophile

Question 5

describe this reaction
BF3+F [-]—>BF4

Answer 5

BF3- the boron has 3 electrons bonded to the fluorine’s and no electron lone pair therefore it is electron deficient

F- : contains 4 lone pairs of electrons therefore is a nucleophile

the F- donates an electron to boron, and boron accepts it. A bond is then formed between one e- in boron which was from F- and one e- from F

Question 6

describe nucleophilic substitution

Answer 6

an electron rich molecule[ nucleophile] attacks the electron deficient species[ electrophile] causing it to give its electron to the species beside it and forming a new bond with the nucleophile

Question 7

explain this nucleophilic substitution
CH3-CH2-CH2Br+ KCN—>CH3CH2CH2C≡N +KBr

Answer 7

1-the carbon is less electronegative than bromine, therefore C becomes slightly positive and Br becomes slightly negative
2-the C≡N- attacks the carbon due to being nucleophilic
3- as carbon cannot form 5 bonds, it transfers one of its electrons to bromine allowing it to break of the bond
4- the C≡N-[nucleophile then attaches to the carbon[electrophile]

Question 8

define substitution

Answer 8

replacement of an atom or group of atom with another atom or group of atom

Question 9

define elimination

Answer 9

elements of starting materials are lost and a pi bond is formed

Question 10

define addition

Answer 10

elements are added to starting material by breaking of pi bond to form sigma bonds