Presentation on theme: "Chapter 4 Table of Contents Section 1 Development of the Atomic Theory"— Presentation transcript:
1 Chapter 4 Table of Contents Section 1 Development of the Atomic Theory AtomsTable of ContentsSection 1 Development of the Atomic TheorySection 2 The Atom
2 Section 1 Development of the Atomic Theory Chapter 4ObjectivesDescribe some of the experiments that led to the current atomic theory.Compare the different models of the atom.Explain how the atomic theory has changed as scientists have discovered new information about the atom.
3 The Beginning of the Atomic Theory Section 1 Development of the Atomic TheoryChapter 4The Beginning of the Atomic TheoryDemocritus, a Greek philosopherAround 440 BCEthought that you could have a particle that could not be cut.Called it an atomos.Aristotle, another Greek philosopher, disagreedBasis: What holds the atoms together?Democritus couldn’t answer the question
4 The Beginning of the Atomic Theory, continued Section 1 Development of the Atomic TheoryChapter 4The Beginning of the Atomic Theory, continuedDemocritus was right:Matter is made of particles,called atoms.atom is the smallest particle into which an element can be divided and still be the same substance.
5 Dalton’s Atomic Theory Based on Experiments Section 1 Development of the Atomic TheoryChapter 4Dalton’s Atomic Theory Based on ExperimentsJohn Dalton published his atomic theory in 1803.His theory statedall substances are made of atoms.Atoms are small particles that cannot be created, divided, or destroyed.Atoms of the same element are exactly alike, and atoms of different elements are different.Atoms join with other atoms to make new substances.Not Quite Correct
6 Definition of an AtomThe smallest particle of an element that retains the properties of the elementHow small?World population in 2000 was about 6 billionOne penny contains 5 billion times more atoms
7 Only with ‘scanning tunneling microscopes Can we See AtomsOnly with ‘scanning tunneling microscopesNanotechnolgy manipulates individual atoms to make very small devicesNext generation of computers will have wires one or two atoms wide (smaller, less power, less heat)