Atomic Theory

Introduction to Atomic Theory
- Atoms are the building blocks of all matter. From stars to
humans to rocks to air, all of these things are composed of
- Atoms are not complicated; they have only 3 parts…
o Electrons which have a negative charge.
o Protons which have a positive charge.
o Neutrons which have no charge.
- The idea of an atom has been around for a long time.
Even around the 4th century BCE, the Greeks had a
concept of the atom.
- While the Greeks had an accurate concept of the atom,
they had no experimental evidence (no tests) to support its
- Almost all the experimental evidence that supports
“atomic theory” has accumulated over the last 200 years.
- No one person deserves all the credit for “atomic theory,”
many people, over a number of years, building on each
others work, gave us the theory we have today.
- This is because science is cumulative.