Atom models

Atom models

1. Democritus' believed that matter was composed of indivisble atoms and void. For him atoms were homogeneous, eternal, invisible and had different characteristics, such as shape and size, wich determined the properties of materials.

   • Democritus

2. Dalton

   • For Dalton, atoms were the smallest portion of matter and were tiny solid spheres, homogeneous, indivisible, indestructible, impenetrable and without charge. Besides that he also stated that atoms of the same element have the same properties and invariant weight, while atoms of different elements have different properties from each other. Dalton believed that during chemical reactions, atoms couldn't be created, destroyed, or altered.

3. Thomson

   • Thomson's atomic model was the first model of atomic structure to indicate de divisibility of the atom. According to Thomson, the atom was a uniform sphere and was formed by electrons, negatively charged particles, embedded in a sphere were there was a positive eletric charge. He believed that the electrons were distributed uniformly through the atom

4. Rutherford

   • According to Rutherford, the atom would have a dense nucleus with a positive electric charge, very small in relation to its total size, with the nucleus, wich would contain practically all the mass of the atom, being surrounded by negatively charged electrons that are located in the electrosphere, wich is basically a space around the nucleus were the electrons are located and orbit in stationary circular paths around the nucleus

5. Bohr

   • Bohr's atomic model shows the atom as a system in wich electrons can only occupy specific orbits around the nucleus, with quantized energies, that is, specific energy values. These orbits are called "Stationary States" and they don't emit radiation. According to Bohr, each electron has a specific amount of energy, and when it absorbs energy, the electron "jumps" to an orbit farther from the nucleus, on the other hand, when energy is released, the electron moves to an orbit closer to the nucleus.

6. Electronic cloud model

   • Currently, we know that atoms are formed by a nucleus that contains protons and neutrons, and by a sort of cloud were the electrons are located. Besides that we know that atoms are divisible and that are even smallest particles than them, such as quarks, but there are still even smallest particles.

7. Work made by Lara Santos, N.º14, 8.ºC

8. Introduction

   • In this work we are going to see the evolution of the attomic models through the years

9. Conclusion

   • As we can in this work the models have changed alot until today and they are probably going to continue to change even after we die

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