IDEAS ABOUT ATOM

2. At the very end of the 19th
century that technology
became advanced enough to
allow scientists a glimpse of
the atom’s constituent part:
the electron, nucleus, proton,
and neutron.

5. The idea that all matter is made up of
tiny, indivisible particles, or atoms, is
believed to have originated with the Greek
philosopher Leucippus of Miletus and his
student Democritus of Abdera in the 5th
century B.C. (The word atom comes from
the Greek word atomos, which means
“indivisible.”)

6. 1.All matter consists of invisible
particles called atoms.
2.Atoms are indestructible.
3.Atoms are solid but invisible
4.Atoms are homogenous.

7. 5. Atoms differ in size, shape, mass,
position, and arrangement.
Solids are made of small, pointy
atoms.
Liquids are made of large, round
atoms.
Oils are made of very fine, small
atoms that can easily slip past each
other.

8. Democritus’ atomic
model was simply a
round sphere with
no electrons,
protons, or neutrons.

10. Chemists use symbols to designate the elements.
Some of the symbols for some elements used by
alchemists are given in figures below.

11. A pseudoscience, called alchemy, dominated 2000
years of chemistry history. Some alchemists are
mystics and some were serious scientists. The serious
ones discovered several elements and prepared mineral
acids. The development of systematic metallurgy (with
the extraction of metals from ore) and the medicinal
application of metals from ore laid the foundations of
modern chemistry.

12. A truly quantitative experiment was
performed by Robert Boyle, who carefully
measured the relationship between the
pressure and volume of air. Boyle insisted the
alchemists’ view that metals were not true
elements and time would come that a way to
change one metal into another would
eventually be found.