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Dalton's Model (Billard Ball Model)
Dalton's atomic theory states that all matter consists of very tiny particles known as atoms. These particles cannot be created, destroyed, or subdivided. Each element has their own type of atoms and their atoms are identical in size, mass, and other properties. He also proposed that compounds are made when atoms of different elements are merged. But, this is not completely a new idea since ancient Greeks had previously proposed that all matter is made of tiny, objects that cannot be divided. -
Thomson's Model (Plum Pudding Model)
After Thomson's discovery of electrons in 1897, many have realized that there are smaller particles in an atom. Atoms are neutral so in 1904, he proposed that electrons are distributed throughout a positive sphere. This is the reason why they called it the plum pudding model, plums in the pudding represents the electrons while the pudding itself represents the positive sphere. He was given a Nobel Prize in 1906 for his discovery. -
Rutherford's Model (Solar System Model)
Rutherford developed the Solar System model. He suggested that an atom mostly contains of empty space with negative electrons surrounding a dense positively charged core, forming the picture of a solar system. He used his famous gold foil experiment to develop this theory. -
Bohr's Model
Similar to the Solar System model, Borh's model shows a positively charged nucleus surrounded by electrons but these electrons are located in certain places. He called these positions shells/orbits. The electrons orbit the nucleus at certain shells, at different levels of energy. This theory explained why atoms emitts light at a certain wavelength or frequencies. -
Quantum Model (Cloud Model)
The cloud model was proposed by Erwin Schödinger in the 1920s. He suggested that an atomis made up of a dense core containing protons and neutrons, which are surrounded by clouds of electrons. The quantum theory states that you can't find out where an electron is located but but can be described with the location of the clouds. Their position is determined by its energy. Bohr's model and the Quantum model structure are in use today.
