Peter Ruddock, PhD, Contributor
Scientists have in their hands and minds, the power to change the world. Chemistry is often described as the central science, linking the 'harder' disciplines, mathematics and physics to the 'softer', living sciences, biology, medicine and social studies. Chemistry is the study of chemicals and how they behave. All things are chemicals. Chemicals are all things. Not just things toxic but everything. Medicines, poisons, things living, things non-living, the smell of rotting garbage, tiny mosquitoes, tasty potatoes, skin, ivory teeth, corrugated pink tongues, the air, sun, moon and stars. All are chemicals. Contemplate the awesome diversity and complexity of nature. Everything so different in form, in function, feel, colour, smell. Then contemplate that they are all made up of exactly the same things.
Almost unbelievably, while chemicals are so diverse in properties, at their core, they are identical. If you divide any chemical into millions and millions of pieces, you will get down to the basic, microscopic building block of that chemical. This basic building block is called the atom. While atoms are different in sizes and properties, every atom is made up of the same three fundamental particles. These particles are the proton, the neutron and the electron.
Building blocks
So, every single thing under the sun is constructed of these three fundamental building blocks. These particles are not visible to the naked eye. In fact they are so small that it would take perhaps a sextillion of them (1 followed by 21 zeros) to fill a bottle cap cover! Protons and neutrons are found in the centre of atoms. Outside the centre, electrons zip around and around in constant motion (a bit like how the earth moves around and around the sun).
A chemical made up of only one type of atom is called an element. At present, 117 different elements are known to mankind. All the elements behave differently from each other. For example, element hydrogen is a flammable gas while element helium, also a gas, is not flammable. Element carbon is a solid that makes up 18 per cent of the human body. It makes sparkly diamonds deep in the bowels of the earth but is also the dark, greasy graphite used to make "pencil lead". Element aluminum obtained from bauxite, is used to make pots and pans. Gold and silver are lustrous metals used to make jewellery.
Identical particles
Why are all the elements so different if their atoms are made up of the same three identical particles, protons, neutrons and electrons? The answer lies in how many protons, neutrons and electrons congregate together in each atom. The hydrogen atom, for example, contains only one proton, one electron and no neutrons. If you add in another proton and another electron, then throw in two neutrons, an entirely different element, called helium, is formed. Unlike hydrogen, helium is not flammable and is used for filling balloons and in the tanks of deep-sea divers. Carbon has six of each particle, while aluminum, a shiny metal, contains 13 protons and electrons but 14 neutrons. Gold and silver atoms are big. Gold contains 79 protons and electrons with 118 neutrons. Silver has 47 protons and electrons plus 61 neutrons. Just changes in the number of these microscopic particles make amazing differences in the properties of each atom and element.
The 117 elements can be combined with each other in a nearly infinite number of ways. Hydrogen, is made of two atoms, joined together by a single bond (hydrogen-hydrogen). If an oxygen atom is stuck between the two hydrogens (hydrogen-oxygen-hydrogen), a clear, tasteless, odorless, very faintly blue liquid, vital to life, is obtained. Water is formed. Squeeze a second oxygen in, and hydrogen peroxide (hydrogen-oxygen-oxygen-hydrogen) a clear, bleaching, antiseptic liquid is obtained. The carbon atom is special. It can form bonds with itself to give long chains, (carbon-carbon-carbon-carbon-etc-etc), a property which is essential to the formation of the muscle, fat and protein tissues which make up life on earth.
Complex compounds
Chemists blend and string these chemicals together to make almost anything. From complex compounds found in nature such as vitamins, steroids and remedies found deep in the jungle, to breakthrough medicines for AIDS and malaria. From domestic products commonly found in kitchens and bathrooms, to synthetic materials such as nylon, polyester, PVC pipes, and Teflon. From nutrition to sustainable energy sources, from new drugs to nuclear energy, chemistry impacts on every area of life.
It is this vast and amazing potential which lies in chemistry and indeed in all of nature, which makes the sciences such powerful and fascinating subjects.
