Topic 1: Molecular Representation, Structure and Bonding

Question 1

Name alkyl groups with 1-10 Cs + hydrocarbon prefix

Answer 1

Methyl (meth)
Ethyl (eth)
Propyl (prop)
Butyl (but)
Pentyl (pent)
Hexyl (hex)
Heptyl (hept)
Octyl (oct)
Nonyl (non)
Decyl (dec)

Question 2

Stereochemistry

Answer 2

Spatial arrangement of atoms

Question 3

VSEPR theory

Answer 3

Electron-electron repulsion determines shape of molecules due to repulsion and attraction to opposite charges

Question 4

Racemate

Answer 4

A 50:50 mixture of the enantiomers of a chiral molecule

Question 5

Kekulé structure of Benzene + why is it prefered?

Answer 5

3 single bonds, 3 double bonds
Mechanistic purposes
Aromatic rings often drawn as resonance forms

Question 6

Draw diisopropylethylamine

Question 7

Draw isopropanol

Question 8

Structure of THF

Question 9

Draw iso-butyl (i-Bu), sec-butyl (s-Bu), tert-butyl (t-Bu)

Question 10

Amides, Esters, Acid chlorides, Anhydrides are…
Draw the general structure of each

Answer 10

…carboxylic acid derivatives

Question 11

Ether general structure

Question 12

Amine general structure

Question 13

Thiol general structure

Question 14

Alkyl halide general structure

Question 15

Alkoxy general structure

Answer 15

RO

Question 16

Ortho

Answer 16

1,2-disubstituted

Question 17

Meta

Answer 17

1,3-disubstituted

Question 18

Para

Answer 18

1,4-disubstituted

Question 19

Acetone structure

Answer 19

Propan-2-one

Question 20

Acetic acid structure

Answer 20

Ethanoic acid

Question 21

Toluene structure

Answer 21

Methylbenzene

Question 22

Phenol structure

Answer 22

Hydroxybenzene

Question 23

Total number of nodes =

Answer 23

n-1
Where n = principle quantum number

Question 24

Number of nodal planes =

Answer 24

I = orbital angular momentum
Ranges from 0 to n-1 where n = principle quantum number
In valence shell of C, n=2 and I has values of 0 and 1, 0=s, 1=p

Question 25

Number of radial nodes =

Answer 25

n - I - 1

Question 26

AOs can combine … or … to form … or …

Answer 26

Destructively (out-of-phase combination)
Constructively (in-phase combination)
Anti-bonding MO with nodal plane
Bonding MO

Question 27

Are bonding and anti-bonding orbitals higher or lower in energy than the AOs?
Where is electrons density in each

Answer 27

Bonding - lower, shared between nuclei
Anti-bonding - higher, anywhere except between nuclei

Question 28

MOs form by overlap between different types of AOs if …

Answer 28

The orbitals have complementary symmetry

Question 29

Sigma bonds are

Answer 29

Symmetrical about the axis linking the 2 nuclei

Question 30

Pi bonds are

Answer 30

Formed from side-on overlap of 2 p orbitals
MOs not symmetrical about nuclear axis

Question 31

3 factors in forming stronger MOs

Answer 31

Orbital having good symmetry
Orbital alignment (end on fashion in p orbitals)
Similar sized orbitals

Question 32

What are bonds ?

Answer 32

Filled molecular orbitals forms from overlap of AOs

Question 33

Hund’s rule

Answer 33

Every orbital in a sub shell is singly filled with 1 electron before any orbital is doubly filled.
All electrons in singly occupied orbitals have same spin

Question 34

Is sp2 or sp3 hybridised orbital higher in energy
What does this mean

Answer 34

sp3
sp2 has more s character so more stable