lecture 2

Question 1

what is orbital hybridisation

Answer 1

combining atomic orbitals to generate combinations of them

Question 2

sp hybrid shape and angle

Answer 2

triple bond
linear
180*

Question 3

sp2 hybrid shape and angle

Answer 3

double bond
trigonal planar
120

Question 4

sp3 hybrid shape and angle

Answer 4

single bond
tetrahedral
109.5

Question 5

if smt is in group 5,, how many bonds are needed for it to be sp3 hybridised

Answer 5

group 5 so 5 e-
needs 5 bonds in order to be sp3 hybridised

Question 6

when do we see single connectivity

Answer 6

when we form discrete molecular systems
when we have units

which only contain a single free connecting unit.

aka a fg that will react with 1 other molecule.

Question 7

example of single connectivity

Answer 7

lewis acid/base adducts
NMe3 + BPh3
N: attacking the B p orbital
——————————————————
condensation reaction between 2 moelcules only!! when both have OH groups,, and water is removed and theyre bonded through the ‘o’.

also called a condensation reaction as water is removed.

Question 8

what is 2 connecting units

Answer 8

when the repeat unit has a connectivity of 2,,, the units can link in a consecutive way to form rings or 1D polymers

this is different to single connectivity as both sides of the molecule has a connective unit to it.

Question 9

what do 2 connectivity units give rise to

Answer 9

either to rings or 1D polymers

Question 10

1 connecting unit

Answer 10

the molecule only has 1 connecting point // connecting group

Question 11

2 connecting units

Answer 11

when the molecules have 2 connecting pointssss // connecting groups and can form 1D polymers or ring systemssss

condensation reactions are a possibility

Question 12

how do we draw a polymer

Answer 12

we draw the repeating unit with extended end lines,, with a bracket going through it and an ‘n’ at the bottom of the bracket.

-(- hello -)-

Question 13

can u react a 1 connecting unit with a 2 connecting unit

Answer 13

yesss!!

we use this in order to cap polymers as a certain length // certain number of repeats

we can use the 1 connectivity at the ends as by connecting to the chain,, they have no more connecting sites.

Question 14

polymers that have been capped can be called

Answer 14

discrete chains

Question 15

how many bonds does a single connectivity unit make

Answer 15

1

Question 16

how many bonds does a double conectivity unit make

Answer 16

it makes 2 bonds
which can either form a ring or 1D polymer

Question 17

what can units with 3 connectivities give ussss

Answer 17

planar sheets ✈️✈️✈️

or closed cagessss🦁🦁🦁

Question 18

what geometries can units with 3 connections haveee

Answer 18

can be trigonal planar //sp2

or tetrahedral with an unreactive site.

Question 19

final structure can be determined byyyyy

Answer 19

coordination geometries ( eg planar,, tetrahedral etccc)

Question 20

whats special about the 4 and 6 connectivity units

Answer 20

their geometries dictate their final lattice geometry

Question 21

4 / 6 connectivity units:
square planar connectivity units give whattt

Answer 21

2D sheets

Question 22

4/6 connectivity units:
tetrahedra connectivity givesss

Answer 22

3D network like graphite

Question 23

6 connections normally giveeeee

Answer 23

3D structures

Question 24

when building main group compounds what must we consider

Answer 24

energetics!!

the stability of the element form or the molecular forms

we normally look at 1D chains and rings

Question 25

we must also consider

Answer 25

thermodynamics

Question 26

what do we mean when we say thermodynamics

Answer 26

entropy and enthalpy

Question 27

when is delta G favoured

Answer 27

when its negative

when its smaller than 0

Question 28

when is delta G not favoured

Answer 28

when its larger than 0.

Question 29

equation for gibbs

Answer 29

delta G = delta H - T delta S

Question 30

when we say covalent bonds,, what do we mean

Answer 30

sigma or pi bonds

Question 31

iss CC or PbPb bonds stronger

Answer 31

CC is stronger

bc it has a smaller atomic radius
which means a greater degree of orbital overlap

which means a stronger bond

the bond is lower in energy

Question 32

the more stable smt isss

Answer 32

the lower energy it hasss

the lower enthalpy it hasss
as it was storing less to begin with <3