Celebrating 18 Years on the Web
Find science on or your birthday


Stories About Chemistry


33. One, Two, Three, Many…

That was about what the counting abilities of primeval man amounted to. His mathematical apparatus included only two quantitative magnitudes, namely, “much,” and “little.”

Cartoon of an excited caveman holding up in one hand Au. He is dressed in an animal skin and carrying a stone axe in the other hand.

People used much the same criterion about a hundred years ago when they tried to estimate the amounts of the separate elements our planet had stored away in its “granaries.” For example, lead, zinc, and silver had found wide usage in practice; there was much of them. Hence, these elements were considered abundant. But the rare earths (lanthanides) were rare because they were hardly ever encountered on Earth.

There was little of them. See how easy it was to reason only a century ago.

The first inspectors of the chemical element storehouses had an easy job to do. Our contemporaries laugh to think of their “activities.”

And how can they help laughing since they can now state exactly how much there is of everything! If they can even tell how many atoms of each element there are in the Earth’s crust. They know for certain that the notorious rare earths are just slightly less abundant in the minerals of our planet than lead, zinc, and silver all taken together.

Scrupulous “accounting” of the reserves of chemical elements started with a scientific feat accomplished by the American scientist Clark. He performed more than 5500 chemical analyses of a great variety of minerals from the tropics and from the tundra, of all kinds of water from lakes in the depths of the wilderness and from the Pacific Ocean. He studied samples of various soils from all parts of the world. This titanic work took him twenty years. Thanks to Clark and other scientists mankind got a quite distinct idea of the abundance of different elements on Earth.

So was born the science of geochemistry. It told wonderful stories such as had never before been known to man. It appeared that the first 26 representatives of the Mendeleyev Table, from hydrogen to iron, form practically the entire crust of the Earth. They constitute 99.7 per cent of its weight, leaving only a “miserly” three tenths of per cent for all the other 67 elements occurring in nature.

Now what is there the most of on Earth? Neither iron, nor copper, nor tin, though man has been using them for thousands of years and the supply of these metals seemed immense, even inexhaustible.

The most abundant element is oxygen. If we place all the Earth’s resources of oxygen on one pan of an imaginary pair of scales and all the rest of the elements on the other, the scales will strike an almost perfect balance. Almost half of the Earth’s crust is oxygen. It is everywhere: in water, in the atmosphere, in an enormous number of rocks, in any animal and plant, and everywhere it plays a very important part.

One quarter of the Earth’s “firmament” is silicon. It is the ultimate foundation of inorganic nature. Further, the elements of the Earth arrange themselves in the following order of abundance: aluminium, 7.4 per cent; iron, 4.2 per cent; calcium, 3.3 per cent; sodium, 2.4 per cent; potassium and magnesium, 2.35 per cent each; hydrogen, 1.0 per cent; and titanium, 0.6 per cent. Such are the ten most abundant chemical elements on our planet.

But what is there the least of on Earth? There is very little gold, platinum and platinum metals. That is why they are valued so highly. But it is a curious paradox that gold was the first of the metals to become known to man. Platinum was discovered before oxygen, silicon or aluminium had ever been heard of.

The noble metals possess a unique feature. They do not occur in nature as compounds but in the native state. No effort is required to smelt them from their ores, that is why they were found on Earth, precisely found, so very long ago.

However, these metals do not “take the cake” for rarity. This lamentable prize goes rather to the secondary radioactive elements. We could rightly call them ghost elements. The geochemists tell us that the amount of polonium on Earth totals only 9600 tons; the amount of radon is still smaller, 260 tons; there is 26 thousand tons of actinium.

Radium and protactinium are veritable giants among the ghosts: they total about 100 million tons, but compared to gold and platinum this is a very small quantity.

As to astatine and francium, they can hardly be classed even as ghosts, because they are still less material. The terrestrial reserves of astatine and francium are measured, ridiculous though it sounds, in milligrams. The name of the rarest element on Earth is astatine (69 milligrams in all of the Earth’s crust). No further comments are necessary.

The first transuranium elements, neptunium and plutonium, have also been found to exist on Earth. They are born in nature as a result of very rare nuclear reactions between uranium and free neutrons. These ghosts can “boast” of hundreds and thousands of tons. But as to promethium and technetium, which are also due to uranium (the latter is capable of spontaneous fission, with its nuclei breaking up into two approximately equal fragments), there is nothing that can be said of them.

Scientists have found hardly perceptible traces of technetium, and are still looking for promethium in uranium minerals. The balance has yet to be invented on which the Earth’s “reserves” of promethium and technetium could be weighed.

< back     next >

- 100 -
Sophie Germain
Gertrude Elion
Ernest Rutherford
James Chadwick
Marcel Proust
William Harvey
Johann Goethe
John Keynes
Carl Gauss
Paul Feyerabend
- 90 -
Antoine Lavoisier
Lise Meitner
Charles Babbage
Ibn Khaldun
Ralph Emerson
Robert Bunsen
Frederick Banting
Andre Ampere
Winston Churchill
- 80 -
John Locke
Bronislaw Malinowski
Thomas Huxley
Alessandro Volta
Erwin Schrodinger
Wilhelm Roentgen
Louis Pasteur
Bertrand Russell
Jean Lamarck
- 70 -
Samuel Morse
John Wheeler
Nicolaus Copernicus
Robert Fulton
Pierre Laplace
Humphry Davy
Thomas Edison
Lord Kelvin
Theodore Roosevelt
Carolus Linnaeus
- 60 -
Francis Galton
Linus Pauling
Immanuel Kant
Martin Fischer
Robert Boyle
Karl Popper
Paul Dirac
James Watson
William Shakespeare
- 50 -
Stephen Hawking
Niels Bohr
Nikola Tesla
Rachel Carson
Max Planck
Henry Adams
Richard Dawkins
Werner Heisenberg
Alfred Wegener
John Dalton
- 40 -
Pierre Fermat
Edward Wilson
Johannes Kepler
Gustave Eiffel
Giordano Bruno
JJ Thomson
Thomas Kuhn
Leonardo DaVinci
David Hume
- 30 -
Andreas Vesalius
Rudolf Virchow
Richard Feynman
James Hutton
Alexander Fleming
Emile Durkheim
Benjamin Franklin
Robert Oppenheimer
Robert Hooke
Charles Kettering
- 20 -
Carl Sagan
James Maxwell
Marie Curie
Rene Descartes
Francis Crick
Michael Faraday
Srinivasa Ramanujan
Francis Bacon
Galileo Galilei
- 10 -
John Watson
Rosalind Franklin
Michio Kaku
Isaac Asimov
Charles Darwin
Sigmund Freud
Albert Einstein
Florence Nightingale
Isaac Newton

who invites your feedback
Thank you for sharing.
Today in Science History
Sign up for Newsletter
with quiz, quotes and more.