science quizwiz

JJ Thomson

Discovered the electron and noticed that an atom can be divided. Found that atoms are made of positive cores with negatively charged particles in them

Proton

Positive charge

Niels Bohr

Popularized the theory that electrons travel in orbit around the atom's nucleus. Introduced the theory that an electron with a higher energy orbit could drop to a lower one.

Ernest Rutherford

Proved that the atoms has a heavy, tiny nucleus. Suggested that the center might be proportional

John Dalton

Theorized that all matter is made of atoms. Every atom of a given element is identical in properties and mass. A compound is a mixture of two or more atoms. A chemical reaction is a rearrangement of atoms

Democritus

Theorized that everything was made of small, invisible particles called atoms. Said that atoms were solid and indestructible and the differ in size, mass and shape

Nucleus

The positively charged center of the atom

Electron

Negative charge

Neutron

Neutral charge