Chem unit 3 ppl

Aristotle, Socrates, Plato, Empedokles

Established four elements that make up the world: fire, air, water, earth and the four basic properties: hot, cold, wet, and dry and the continuous theory of matter

Democritus

proposed the discontinuous theory of matter and called the smallest particle an atom

Discontinuous Theory of Matter

all matter is composed of atoms, there's a void between between atoms, atoms are solid and homogeneous different in size shape and weight.

Roger Bacon

made the scientific method

Alchemists

developed many experimental methods and equipment

antoine lavoisier

law conservation of mass

Joseph proust

law of definite composition

John Dalton

Daltons Atomic Theory

Law of Multiple Proportions

when 2 elements combine to make 2 different compounds and if the masses of one of the elements in those compounds are the same, then the ratio of the masses of the other element in those compounds will be a ratio of small whole numbers

Daltons Atomic theory

all matter is composed of atoms, atoms of an element are identical, and atoms cannot be subdivided

William Crookes

discovered cathode rays(first evidence of electrons)

J.J. Thomson

discovered electron and calculated the charge to mass ratio of one

Max Planck

Determined energy is quantized, quantum theory

Albert Einstein

explained the photoelectric effect

Robert Millikan

Calculated the charge and mass of an electron

Ernest Rutherford

discovered the nucleus

Henry Moseley

Discovered that the positive charge of the nucleus increases by one unit from one element to the next

Niels Bohr

Developed the planetary model of the atom

Rutherford

discovered the proton

Louis de Broglie

concept of wave-particle duality of matter

Erwin Schrodinger

Developed wave equations and viewed electrons as continuous clouds

Werner Heisenberg

Heisenbergs uncertainty principle: it isn't possible to know the velocity and position of a particle at the same time

James Chadwick

discovers neutron