Chem. Chapter 4 - Atomic Structure

Front 1

Democritus

Back 1

suggested that the world was made of two things: empty space; small particles that he called "atoms"

Front 2

Aristotle

Back 2

proposed that matter was continuos and not made up of smaller particles.

Front 3

Isaac Newton and Robert Boyle

Back 3

believed in the atomic nature of matter but had no experimental proof.

Front 4

John Dalton

Back 4

studied the works of other scientists to try to explain the nature of matter

Front 5

Antoine Lavoister

Back 5

discovered that when a chemical change takes place in a close system, the total mass does not change.

Front 6

the law of conservation of mass

Back 6

matter cannot be created or destroyed, only changed in form. (Levoister)

Front 7

Joseph Proust

Back 7

observed that specific substances always combine in simple whole number rations to form compounds.

Front 8

Law of definite Proportions

Back 8

specific substances always combine in simple whole number rations to form compounds.

Front 9

Dalton's Atomic Theory

Back 9

a. All matter is composed of very small particles called atoms.
b. Atoms cannot be broken into smaller particles.
c. All atoms of one element are exactly alike and atoms of different elements are not alike.
d. Atoms combine in simple whole number ratios to form compounds.

Front 10

Law of multiple proportions

Back 10

The ratio of masses of one element that combine with a constant mass of another element can be expressed in small whole numbers.

Front 11

J. L. Gay-Lussac

Back 11

noted that under constant conditions of temp. and press, the volumes of reacting gases and gaseous products are in a ratio of small whole numbers.

Front 12

Amedo Avogadro

Back 12

stated that equal volumes of gases, under the same conditions, have the same numbers of particles

Front 13

J.J Thompson

Back 13

used the cathode ray tube to determine the charge mass ratio of electrons.

Front 14

Robert Milikan

Back 14

obtained the first accurate measurement of an electron's charge.

Front 15

James Chadwick

Back 15

discovered high energy particles with no charge and with essentially the same mass as protons (neutrons)