Science Library - free educational site

Organic Chemistry Introduction


Carbon is the basis of life. Because of its central role in biology, and the very large number and variety of compounds and processes involving carbon, it has its own subject within chemistry. organic chemistry.

Carbon is a non-metal element, and is found in the second row of the periodic table, with valency 4. The first electron energy shell has two electrons and is therefore full. The second shell needs 8 electrons, and neutral carbon has only 4. When it bonds with other atoms, often hydrogen, oxygen, and nitrogen, it forms very strong bonds.

The bond enthalpy C-C is 348 kJ mol$^{-1}$. C-H (412), O=O (496), C=O (743), O-H (463)

Methyl group

The history of chemistry is a fascinating journey. Modern chemistry evolved out of fields like alchemy, which combined superstition, material greed and nutty religion with practical experimentation.

The struggle to understand the difference between elements and compounds lasted two hundred years, from Boyle in the mid-1600s to the creation of the Periodic Table by Mendeleev in 1860.

Abandoned Concepts

4-Element System

The ancient Greeks figured that all the matter of the world could be reduced to just four elements: earth, water, air, and fire.

This concept prevailed until the early 1800s, by which time scientists like Priestly, Lavoisier, and Davey had shown that substances could be broken down to many more distinct elements, and that fire was not an 'element', but energy.

Potassium oxidising in water, and igniting hydrogen

A vital discovery by Humphrey Davy in 1807 was electrolysis, which allowed him to isolate potassium from the compound potash, and sodium from salt. These discoveries, and that of oxygen and hydrogen recombining to form water, paved the way to the distinction of elements and compounds.

Today, the Periodic Table describes the properties of all 92 naturally occurring elements. Since there are no gaps, it is assumed there are no more. Larger elements can be created artifically in the laboratory, but they are unstable and short-lived.

Phlogiston Theory

The phlogiston theory was first proposed by Johann Becher in 1667, and strongly championed by Joseph Priestley till put to rest by Antoine Lavoisier in the 1780s.

The word derives from the Ancient Greek [φλογιστόν phlogistón] for combustion, or burning up. The theory proposed that combustion was due to an element called phlogiston. All combustible substances supposedly contained this element, and it was released during combustion.

Although precursing the understanding of oxidation, its influential adherents obstructed scientific progress in the field.

Content © All rights reserved. Created : May 7, 2015 Last updated :May 7, 2016

Latest Item on Science Library:

The most recent article is:


View this item in the topic:

Vectors and Trigonometry

and many more articles in the subject:

Subject of the Week


Environmental Science is the most important of all sciences. As the world enters a phase of climate change, unprecedented biodiversity loss, pollution and human population growth, the management of our environment is vital for our futures. Learn about Environmental Science on

Environmental Science

Great Scientists

Charles Darwin

1809 - 1882

Charles Darwin is one of the most famous of all scientists, and a true hero of science. His theory explaining the mechanisms of evolution were published in his book On the Origin of Species (1859), which launched a storm of controversy from religious dogma adherents.

Portrait: Charles Darwin

Quote of the day...

The next morning began with a brief series of howl screeches, acoustically representing the dying moments of the entrance gate hinges. Considering the gate was not even closed, let alone locked, it would be safe to say whoever they were, these were not your run of the mill guests. Not that I am suggesting guests should be allowed to run the mill.

ZumGuy Internet Promotions

IT information forum by Sean Bone