Author: J R Reid

Organic Chemistry – Introduction

DefinitionKeywordsThe ComponentsExamplesThe BondsTypes

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 electricityMolecule – a group of atoms joined together with covalent bonds. They can be elements or compoundsCovalent bonds – a bond between two non-metal 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 bondsHydrogen – 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 bondsHalogens – 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:

CC

O

H

H

H

H

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=CTriple 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:

C C

H

H

H

H

C CH 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

Methyl propanoate

Ester

Chloro methane

Haloalkane

Ethanoic acidCarboxylic acid

EthanolAlkanol(Alcohol)

ExampleFunctional GroupType

Chain Lengths

Each type of chemical can exist with various numbers of carbons bonded together into a chainLater we will learn that the name of each organic molecule is determined by the length of the longest carbon chain in the molecule

CC H

H

H

H

H

H

C C CH

H

H H

H H

H

H

C

H

HH

H