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Ancient Greek Theory
At the begging of the times, ancient greeks thought that any material was composed by 4 elements: air, fire, water, and earth -
Gilliard Ball Model
This theory was created by John Dalton (9).Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions. -
Plum Pudding Model
This theory was created by Thompson. J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup."In 1911, Rutherford showed that Thomson's model was "wrong": the distribution of positive and negative particles was not uniform. Rutherford showed that the atom contains a small, massive, positively nucleus -
Nuclear Atom
Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus.Based on these results, Rutherford proposed the nuclear model of the atom. Based on his experimental results, Rutherford made the following conclusions about the structure of the atom. The main problem with Rutherford's model was that he couldn't explain why negatively charged electrons remain in orbit when they should instantly fall into the positively charged nucleus. -
Solar System Model
Bohr model, description of the structure of atoms, especially that of hydrogen, proposed by the Danish physicist Niels Bohr. The Bohr model of the atom, a radical departure from earlier, classical descriptions, Bohr's model of hydrogen is based on the nonclassical assumption that electrons travel in specific shells, or orbits, around the nucleus. Bohr's model was bad theoretically because it didn't work for atoms with more than one electron. -
Electron Cloud, Quantum Mechanics Model
Erwin Schrödinger, an Austrian physicist, took the Bohr atom model one step further. Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom. And at the moment, this theory is the most modern in basic chemistry
