Transcript Organic Chemistry – Introduction

Organic Chemistry
– Introduction
Definition
Keywords
The Components
Examples
The Bonds
Types
Author: J R Reid
What is Organic Chemistry?
Once upon a time chemists believed that
certain chemical such as glucose, alcohol,
proteins and petrol could only be made by
living organisms. Therefore they were
given the name ‘organic chemicals.’
It was later discovered that they could be
made in the laboratory and that they all
had one thing in common – they were all
compounds of carbon
Keywords – Before we begin
There are a number of key words that we
must revise before we begin:
Non-metals – A group of elements that are
found on the right-hand side of the periodic
table. They are not malleable, lustrous and
ductile, and they are poor conductors of heat
and electricity
Molecule – a group of atoms joined together
with covalent bonds. They can be elements or
compounds
Covalent bonds – a bond between two nonmetal atoms, where the outer shell electrons
are shared to complete the electron shells
The Components of Organic
Chemicals
The atoms that make up organic chemicals can be
compared to Lego® blocks. They have a certain number of
connections (1, 2 or 4) and they can be arranged in a
number of different ways:
Carbon – the main building block of organic chemicals – it can
form four covalent bonds
Oxygen - this ‘add on’ can form two covalent bonds
Hydrogen – this atom basically fills in any free bonds – it has
the ability to make one bond only
There are a few other non-metals that we will look at this
year but they are less common than the one mentioned
above:
Nitrogen – can form three bonds
Halogens – can form one bond
Examples of Organic
Molecules
Organic molecules can be drawn in a
number of different ways. Here is the
same molecule (ethanol) – note the
number of bonds that each component
has formed:
H
H
H
C
C
H
O
H
H
The Bonds
Organic molecules only form covalent bonds but
there are a few variations:
Double bonds – when an atom forms two covalent
bonds with another atom. They are drawn like this: C=C
Triple bonds – when an atom forms three covalent
bonds with another atom. They are drawn like this: C≡C
Here are some examples of each – note how many
bonds each component has:
H
H
C
H
C
H
H
C
C
H
Types of Organic Molecules
There are a number of different types of organic
chemicals. We identify each type by a combination
of atoms that it will contain. This combination is
called a functional group
These examples are called Hydrocarbons
Type
Functional Group
Example
Alkane
(Single bonds)
Methane
Alkene
(Double bonds)
Ethene
Alkyne
(Triple bonds)
Propyne
Type of Organics II
Here are some others that contain oxygen or halogens
Type
Functional Group
Example
Alkanol
(Alcohol)
Ethanol
Carboxylic
acid
Ethanoic acid
Ester
Methyl
propanoate
Haloalkane
Chloro
methane
Chain Lengths
Each type of chemical
can exist with various
numbers of carbons
bonded together into
a chain
Later we will learn
that the name of each
organic molecule is
determined by the
length of the longest
carbon chain in the
molecule
H
H C H
H
H H
H C C H
H H
H H H
H C C C H
H H H