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4.1. Early Models of the Atom. Early Models of the Atom An atom is the smallest particle of an element that retains its identity in a chemical reaction. Philosophers and scientists have proposed many ideas on the structure of atoms. 4.1. Early Models of the Atom.
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4.1 Early Models of the Atom • Early Models of the Atom • An atom is the smallest particle of an element that retains its identity in a chemical reaction. • Philosophers and scientists have proposed many ideas on the structure of atoms.
4.1 Early Models of the Atom • Democritus’s Atomic Philosophy • How did Democritus describe atoms? Democritus
4.1 Early Models of the Atom • Democritus believed that atoms were indivisible and indestructible. • Democritus’s ideas were limited because they didn’t explain chemical behavior and they lacked experimental support.
4.1 Early Models of the Atom • Dalton’s Atomic Theory • How did John Dalton further Democritus’s ideas on atoms?
4.1 Early Models of the Atom • By using experimental methods, Dalton transformed Democritus’s ideas on atoms into a scientific theory. • The result was Dalton’s atomic theory.
4.1 Early Models of the Atom All elements are composed of tiny indivisible particles called atoms.
4.1 Early Models of the Atom • Atoms of the same element are identical. The atoms of any one element are different from those of any other element.
4.1 Early Models of the Atom • Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.
4.1 Early Models of the Atom • Chemical reactions occur when atoms are separated, joined, or rearranged. Atoms of one element are never changed into atoms of another element in a chemical reaction.
4.1 Sizing up the Atom • Sizing up the Atom • What instruments are used to observe individual atoms?
4.1 Sizing up the Atom • Despite their small size, individual atoms are observable with instruments such as scanning tunneling microscopes.
4.1 Sizing up the Atom • Iron Atoms Seen Through a Scanning Tunneling Microscope
4.1 Section Quiz • 1. The ancient Greek philosopher credited with suggesting all matter is made of indivisible atoms is • Plato. • Aristotle. • Democritus. • Socrates.
4.1 Section Quiz • 2. Dalton's atomic theory improved earlier atomic theory by • teaching that all matter is composed of tiny particles called atoms. • theorizing that all atoms of the same element are identical. • using experimental methods to establish a scientific theory. • not relating atoms to chemical change.
4.1 Section Quiz • 3. Individual atoms are observable with • the naked eye. • a magnifying glass. • a light microscope. • a scanning tunneling microscope.
