Chemistry - The Atom

Dalton

first to put forward the idea of an atom

Crookes

discovered cathode rays

Thomson

discovered electron, charge to mass ratio of electron and plum pudding model of the atom

Millikan

discovered the charge and mass of an electron

Rutherford

discovered the nucleus and the proton

Chadwick

discovered the neutron

Dalton’s Atomic Theory

all matter is made up of small indivisible particles called atoms. these atoms cannot be created or destroyed

Cathode

connected to negative of battery

Anode

connected to positive of battery

Cathode Rays

• streams of electrons

• travel in straight lines from the cathode to the anode

• deflected by electric and magnetic fields

• have sufficient energy to move a small object

E/M

charge to mass ratio of an electron

Plum Pudding Model

a sphere of positive charge with electrons embedded in it

Oil Drop Experiment

used by Millikan to discover the charge to mass ratio of an electron

Gold Foil Experiment

experiment performed by Rutherford when he discovered the nucleus

Beryllium

was bombarded with alpha particles by Chadwick when he discovered the neutron