Chemistry First Test

Democritus

Found that all matter is divided into smaller and smaller pieces until single indivisible particle was reached (atom)

John Dalton

- All matter is composed of tiny indivisible particles called atoms

- all atoms of the same element have identical properties

- atoms of different elements have different properties

- Law of Constant Composition

- Law of Conservation mass

Law of Constant Composition

Atoms of two or more elements can combine in constant ratios to form new substance

Law of Conservation of Mass

In a chem reaction, atoms join together or separate but are not destroyed

J.J Thompson

- provided evidence of electrons

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