important ppl chem

Beleived that there were fundamental building blocks→ atoms= indivisable

Democritus

No atoms, all mater is made of four elements, earth, wind, fire ,water

aristotle

Matter is composed of small particles, all atoms of a given element are identical, all indivisible and indestructible. Law of conservation/ deff proportions

John Dalton

Discovered the electron, using tube to generate cathode ray, mass of particles much smaller then H+ moved towards positive charge, discovered charge to mass ratio

JJ Thomsom

Plum pudding model. small negatively charged particles surrounded by a positively charged sphere.

Thomson

Oil drop expirment→ charge of electron

new charge mass, calc mass of electron 1/1840 of a h+

greatest common factor of measurments=charge on electron

Robert milikan

Gold foil expiriment

nuclear model of atom

positively charged center= nucleus

james chadwick discovered neutrons

Rutherford

arranged elements by mass

John Newland

Dimitri mendeleeve

Mass=properties

mass= atomic #

Henry Moseley