Atomic Theory and Early Chemists

A set of vocabulary flashcards reviewing early scientists, chemical laws, and John Dalton's Atomic Theory of Matter based on lecture notes.

Democritus

Philosopher (460 B.C.-370 B.C.) who proposed that the world is composed of matter made of tiny indivisible and indestructible particles called atomos.

Atomos

The term used by Democritus (460 B.C.-370 B.C.) to describe tiny indivisible and indestructible particles that compose matter.

Antoine Lavoisier

Scientist known for proposing the Law of conservation of matter.

Law of Conservation of Matter

The principle proposed by Antoine Lavoisier regarding the conservation of matter.

Joseph Proust

Scientist who established the Law of constant composition in 1799.

Law of Constant Composition

Law established by Joseph Proust in 1799 stating that the same compound always contains the same elements in the same proportions by mass.

John Dalton

Scientist (1766-1844) who consolidated early atomic ideas into the Atomic Theory of Matter.

Atomic Theory of Matter

Theory created by John Dalton (1766-1844) consisting of four postulates regarding the structure and behavior of matter and atoms.

Dalton's First Postulate

All elements are composed of tiny indivisible particles called atoms.

Dalton's Second Postulate

Atoms of the same element are identical, and the atoms of any one element are different from those of any other element.

Dalton's Third Postulate

Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.

Dalton's Fourth Postulate

Chemical reactions occur when atoms are separated from each other, joined, or rearranged in a different combination, but atoms of one element are never changed into atoms of another element as a result of a chemical reaction.