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The Atom. Aristotle – the four basic elements -Earth -Air -Water -Fire. Democritus Follower of Leucippus An Atomist Coined the word atomos meaning uncuttable or the smallest particle of matter. 2000 years later John Dalton – School Teacher Five main points of Dalton's atomic theory
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Aristotle – the four basic elements -Earth -Air -Water -Fire
Democritus • Follower of Leucippus • An Atomist • Coined the word atomos meaning uncuttable or the smallest particle of matter
2000 years later John Dalton – School Teacher Five main points of Dalton's atomic theory -The atoms of a given element are different from those of any other element; the atoms of different elements can be distinguished from one another by their respective relative atomic weights. -All atoms of a given element are identical. -Atoms of one element can combine with atoms of other elements to form chemical compounds; a given compound always has the same relative numbers of types of atoms. -Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together. -Elements are made of tiny particles called atoms.
Plum Pudding Model of the Atom JJ Thompson
Atomic Number: The number of protons in the nucleus of an atom Mass Number: The total number of protons and neutrons on a nucleus Atomic Number Symbol Atomic Mass
Isotope: Atoms of the same element that have different masses