4.1 –Early Theories of Matter - Weebly

4.1 ? Early Theories of Matter

? OBJECTIVES: Students will be able to (SWBAT)

1. Compare and contrast the atomic models of Democritus and Dalton

? 7 lecture/8 reading questions ? 5-sentence summary

Notes: Early Theories of Matter (4.1)

Democritus' Ideas

? Greek philosopher who lived over 2000 years ago ? Democritus suggested that "atomos" or indivisible

particle existed.

1) Matter is mostly empty space 2) Matter is made of atoms that are solid, homogeneous and

indivisible 3) Different elements are just atoms of different sizes 4) Different physical & chemical properties of matter are due

to size, shape and movement of atoms 5) Changes (chemical) in matter result from changes in the

grouping of atoms No one believe him at the time because he couldn't evaluate his theory or provide evidence (no experiments)

Dalton's Ideas: 1803 ? 1808 (based on experiments)

1) All matter composed of small particles called atoms

2) All atoms of each element are the same (size, shape, mass, properties)

3) Atoms cannot be created nor destroyed 4) Atoms cannot be further divided 5) Atoms combine in whole number ratios to form

compounds 6) Atoms rearrange, combine or separate in chemical

changes (reactions)

These have been proven wrong in modern theories.

Dalton's Billard Ball Model of the Atom

? Proposed atoms are sphere-shaped particles, and each element has a unique model

Dalton's Billiard Ball Atom

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