1. ATOMIC STRUCTURE and the PERIODIC TABLE

2. ATOMIC STRUCTURE Democritus – teacher, 4th c. BC
Atomist school of thought
Matter is composed of tiny particles called atoms
Atoms are invisible, indestructible fundamental units of matter

3. DEMOCRITUS

4. JOHN DALTON ( )

5. JOHN DALTON (1766-1844) English school teacher
Studied the ratios in which elements combine in chemical reactions
formulated Dalton’s Atomic Theory

6. DALTON’S ATOMIC THEORY
1. All elements are composed of submicroscopic, indivisible particles called atoms.
2. Atoms of the same element are identical. The atoms of any one element are different from those of any other element.

7. DALTON’S ATOMIC THEORY
3. Atoms of different elements can physically mix together, or can chemically combine in simple WHOLE number ratios to form compounds.

8. DALTON’S ATOMIC THEORY
4. Chemical reactions occur when atoms are separated, joined or rearranged.
Atoms of one element are never changed into atoms of another element as a result of a chemical reaction.

9. ATOMIC THEORY Much of Dalton’s theory still holds today
there are revisions to parts of Dalton’s theory

10. THE ATOM
Smallest particle of an element that retains the properties of that element
How small are they?
If you placed 100,000,000 Cu atoms side by side they would form a line only 1 cm long.