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300
Democritus
300 BC
Atoms are indivisible particles
Atoms are the smallest particle of matter -
Dalton
"The Solid Sphere Model"
Atoms are indestructible speheres or balls
This theory confirmed the basic Laws of Conservation of Mass and definitie Proportions -
Thomson
"The Raisin Bun Model"
Other names include chocolate chip cookie model
Atoms are solid spheres with a positive mass or core with little negative particles scattered throughout the positive mass
Shows signs of electron and proton existence
Indicated idea of a nucleus -
Rutherford
"The Planetary Model"
Rutherford's famous gold leaf experiment proves that the nucleus is positive and there are electrons on the outside of the nucleus
First modern view of the atom
Suggests that the atom is actually mostly just empty space -
Bohr & Rutherford
Found by using a atomic spectra that electrons are placed in definite rings or orbitals around nucleus
Places electrons in definite energy levels
Explains the rolde of valence electrons in bonding and ionic and covalent bonding -
Modern Atom
"Quantum Mechanical Model"
Many scientists contributed to the modern day model of the atom
Some of those scientists include: Einstein, Planck, Maxwell, and Fermi
Has electron cloud surrounding nucleus
