Why did Democritus, Thomson, Rutherford and Bohr draw the atom in the way that they did?

Question

I'm doing a Science assignment on the history of the atom, and I'm having some trouble finding out why Democritus, thomson, rutherford and bohr made models of the atoms the way they did. What I mean is, why did they think that the atom looked like that?

sources would be appreciated

Answer 1

Here is the complete list of the evolution of the atomic model:

Democritus - Democritus concluded that matter could not be divided into smaller and smaller pieces forever. Eventually, the smallest piece of matter would be found. He used the word atomos to describe the smallest possible piece of matter.

Dalton's atomic model is a sphere. He believed that it has mass but no internal structure.

Thomson's plum pudding model- He thought that the raisins in the bread are the electrons and the bread is the positively charged surface that's why his model looked that way(a positively charged sphere with electrons embedded into it)

Rutherford's nuclear model- He constructed the model in that way because of the Alpha scattering experiment or goldfoil experiment. He pictured the atom as mostly empty space to explain why most alpha particles passed through undeflected. This is a tine, positive central core called the NUCLEUS where the mass of the atom is concentrated. When an alpha particle occasionally runs into the nucleus, it is repelled. The electrons move around the nucleus.

Bohr's planetary model - Electrons move in definite orbits around the nucleus, like planets moving around the nucleus. Bohr proposed that each electron moves in a specific energy level.

Electron cloud model - Electrons are scattered; explain the emission of light