Intro to organic concepts

Question 1

What types of hybridisation are there?

Answer 1

sp3, sp2 and sp hybridisation

Question 2

Explain the characteristics of sp3 hybrid orbitals

Answer 2

This happens when there are 4 sigma bonds

Each sp3 orbital contains 1/4s and 3/4p character and is directed towards the corners of a regular tetrahedron to minimise repulsion thus bond angle is 109.5 degrees

Question 3

Explain the characteristics of sp2 hybrid orbitals

Answer 3

This occurs when there are 3 sigma and one pi bond.

Each sp2 orbital has 1/3 s character and 2/3 p character. They are coplanar and at 120 degrees to each other.
C-C pi bond formed by 2pz orbitals on each C overlapping laterally resulting pi electron cloud is distributed above and below the plane of atoms.

Question 4

Explain benzene ring bonds

Answer 4

2pz orbital on each C overlaps with adjacent 2pz orbital on either side resulting in continuous donut-shaped electron clouds, one above and below the plane of atoms.

The pi electrons are delocalised around the whole ring and this is known as resonance. each c-c is a partial double bond

Question 5

Explain how sp orbitals are like

Answer 5

happens when there are 2pi and 2 sigma bonds. bond angle of 180 degrees in a linear shape.

pi bonds formed by lateral overlap of 2py and 2pz orbitals

Question 6

What are the diff types of organic reactions
and what characteristics do they have?

Answer 6

elimination addition substitution condensation hydrolysis oxidation and reduction

nucleophilic electrophilic and free radical

Question 7

sub?

Answer 7

an atom of grp replaces another

Question 8

addition?

Answer 8

2 or more molecules combine to form a single product where a multiple bond is broken in the process

Question 9

elimination?

Answer 9

removal of a grp of atoms of groups from 2 adjacent atoms to form multiple bond

Question 10

condensation

Answer 10

2 or more molecules combine to form a larger molecule together with the loss of a small molecule like h20.

Question 11

What are nucleophiles, electrophiles and free radicals

Answer 11

nucleophiles - e- rich species with a lp of electrons that can be donated to form a new bond e.g attacks carbon bonded to highly electronegative element

electrophiles - electron deficient species with vacant orbitals to accept electron pair e.g attacks pi bonds that are electron rich

free-radical - species with unpaired electron and is highly reactive cos of that

Question 12

what is homolytic fission?

Answer 12

two shared electrons in the C bond are split equally between 2 atoms. indicated by half arrow to each of the atoms involved in the bond

Question 13

what is heterolytic fission?

Answer 13

2 shared electrons in the bond are split unequally between 2 atoms. indicated by arrow to one atom

Question 14

What factors affect reactivity of organic compounds?

Answer 14

resonance effect, electronic effect and steric effect

Question 15

how does resonance affect reactivity?

Answer 15

In molecules with alternate double and single bonds, adjacent p orbital can overlap with one another allowing the pi electrons to move over a greater area of space, so they are delocalized and have added stability

Question 16

How does electronic effect affect reactivity?

Answer 16

alkyl groups have an electron-donating inductive effect while highly electronegative atoms have an electron-withdrawing inductive effect. This will either disperse the charge or intensify it , stabilizing/destabilizing it. Strength of inductive increases with number of groups and decreases with distance away from the charge.

Question 17

How does streic effect affect?

Answer 17

Steric hindarance where large groups on a molecule hinder a reaction