-
Democritus believed that atoms were uniform
-
postulated a fifth atomic type
-
Found the four basic elements fire wind water earth
-
He discovered the atomic number is the number of positively charged protons in an atom
-
He proposed that elements are composed of 'corpuscles' of various types and sizes
-
mass of products and reactants in a chemical reactions is always the same.
-
Adams are small solid particles of matter
-
Proposed that all matter has atoms
-
qual volumes of gases at the same temperature and pressure contain equal numbers of molecules
-
He invented the periodic table
-
All atoms have negatively charged particles
-
They isolated radioactive radium salts from the mineral pitchblende
-
electrons surrounded positively charged particles
-
Mathematically prove the existence of the atom
-
There is a fundamental electric charge
-
the atom is mostly empty space
-
theory for the hydrogen atom
-
Electrons orbit the nucleus like plan
-
He developed the quantum mechanical model of the atom
-
The nucleus is surrounded by a cloud of electrons
-
Mathematically predicted where a electron will be in an atom
-
Discovered the neutron