Atoms - Build Molecules

The Atom
One of the very basic building blocks of all things in existence is the atom – indeed, for many years it was thought to be the smallest indivisible unit of matter. This indivisible nature is reflected in the origins of the name “atom” – it is Greek for “that which cannot be cut.” The Greek origin of the name is a fitting term for this basic unit, as the concept of what we now know today as the “atom” was originally imagined by early Greek philosophers whom spent great time theorizing about the building blocks of the world around them. The Greeks built their concept of the atom from some original thoughts about matter developed by the ancient Indian schools that specialized in Hindu theories about life. It is unknown exactly how these thoughts reached Greek culture (or if they originated independently) but in 475 BCE the Greek educator and philosopher Leucippus popularized the Western concept of atomism, thereby becoming the father of the idea. It was Leucippus’ student, Democritus, however, that gave the movement – and the atom – a name.

For centuries the atom remained little more than a concept, even when 18th century chemists provided a scientific practicality and reasoning for their existence. Up until 1661, even the most advanced of chemists believed that all matter composed solely of one of the four elements: water, fire, air, and earth. The Greek ideas of Democritus were reborn when fellow philosopher, Irishman Robert Boyle, penned the breakthrough scientific literary work “The Sceptical Chymist” [sic]. The work was controversial as he credited the Greek atom to be the true building block of the world over the long-held four elements.

Little more work was made on the atom concept until 1803 when educator John Dalton of London theorized that various chemicals dissolve better in water due to the existence – and reactions of – various kinds of atoms. This theory was implemented and evolved over a number of years, eventually leading Albert Einstein to write a mathematical equation in 1905 to explain the potential motion of atoms. Building upon this work, the actual size and volume of (along with undeniable existence of) atoms was made measurable by Jean Perrin, a French physicist.

Throughout this entire time – from the Greek concept to the Einstein mathematical formula and subsequent work of Perrin, scientists from around the world believed that the atom stayed true to its Greek name – that it really was the smallest indivisible building block of existence. This was disproved in 1897 through the work of J.J. Thomson, a physicist. Thomson discovered the electron and devised the Plumb Pudding Model: the idea that the atom was full of randomly-spaced positive and negative energy. For this discovery and theory Thomson won the Nobel Prize for Physics in 1906.

Two years later the Plumb theory was set aside when physicist Ernest Rutherford devised what has become known as the Solar System Model, which proposed the idea of a nucleus surrounded by electrons. This idea was further improved upon in 1913 when physicist Neils Bohr assigned orbits to these traveling electrons. Both Rutherford and Bohr received Nobel Prizes for their discoveries as well, in 1908 and 1922, respectively.

The next several decades would be spent learning about the atom and its varying parts, eventually coming to the discoveries that led to the established knowledge of the atom today. While the complete story of the atom, its parts, and uses are extremely deep and in some cases still being tested and realized, the basics are as follows: the atom is essentially devised of three main parts: subatomic particles, the nucleus, and the electron cloud.

Three main subatomic particles exist within an atom: the electron, proton, and neutron. While the neutron has no electrical charge to it whatsoever, the other two components have electrical charges: the electron has a negative charge while the proton has a positive charge. Various types of atoms differ slightly in their charge ratios and subatomic particle arrangement; however, this is the basic building block example of the atom. It is important to note that the charges and their possible energy levels in the subatomic particles is the source of nuclear energy – an energy that has been used for good and bad purposes over the years (ranging from nuclear power plants for powering cities to the nuclear bomb). The nucleus is the resulting particle from various bonds between protons and neutrons; again, this can vary by atom type. The final element, the electron cloud, is a force which surrounds the nucleus and it is electromagnetic. This force, in essence, is what binds the atom together and creates stability. Of important note, the electron cloud concept is the successor of both the Plumb and Solar System Models of the early 20th century.

Today scientists and physicists are still experimenting with the atom – both in an effort to understand matter and to harness energy. This simple building block of life is also the most complex; the history of the atom will keep evolving with science for generations to come.