9Introduction
Elemental
building blocks
Elements in and around us
About 99 per cent of the human body is made from just
six elements, though they are combined together to form
thousands of different compounds. On the other hand,
Earth’s atmosphere is a mixture of gases, most of which
are pure elements. About 99 per cent of the air is made
from nitrogen and oxygen.ROBERT BOYLE
Bismuth crystals Gold crystalsPhosphorus 1%
Calcium 1.5%Others 1%Hydrogen 10%Carbon
18.5%Nitrogen 3%Human body Earth’s atmosphereArgon 0.9%Others 0.1%Nitrogen
78%The first person to use
science to understand
the elements was the
Irish scientist and inventor
Robert Boyle. He pursued
science through reason,
and in the 1660s he
performed the first
chemistry experiments
to show that much of
what the alchemists
believed was wrong.Alchemy and mysticism
Chemists are scientists who study elements and compounds.
However, before they existed, the alchemists were medieval
researchers. Believing in a mixture of science and magic,
alchemists tried to change ordinary metals (such as lead)
into gold. They failed because elements cannot be changed
from one type to another. But, in the process, they discovered
many new elements and developed several processes that
chemists still use today.Iranian alchemists in their workshopOxygen
65%Ancient ideas
The idea of elements is very old, dating
back about 2,600 years to ancient Greece.
However, Greek thinkers believed that
the world was made of just four elements:
earth, water, fire, and air. Empedocles, an
influential scholar, was the first to propose
that these elements made up all structures.
Only much later did scientists learn that
none of these are actually elements. For
thousands of years, everybody from ancient
Egyptian priests to medieval European
alchemists, speculated about the definiton
and classification of an element.Earth WaterAir FireOxygen 21%008-009_Elemental_building_blocks.indd 9 12/12/16 5:36 pm