ATOM THEORY

1. Leucippos and Demokrius

Atom is the smallest part of a substance that can not be divided.

2. John Dalton

Atom is:

- The smallest particles contained in a substance

- Can not be described and can not be converted into other atoms

- Different element atoms with atoms of other elements

- Atoms of certain elements have the same properties

- During the reaction, the atom has not changed but its composition is different.

3. J. J. Thomson

Atom is:

- Is a solid ball, where protons and electrons scattered inside

- A positive charge = negative charge

4. Rutherford

Atom is:

- Based on the alpha ray scattering experiment

- Consists of atomic nuclei which is the center of mass and positively charged, while the negatively charged electrons spinning around the nucleus of the atom.

weaknesses:

- Based on Maxwell's theory, the atom is unstable

- A continuous spectrum when the spectrum of atomic lines.

5. Niels Bohr

Atom is:

- The basis of Rutherford's atomic theory and quantum theory

- Consists of atomic nuclei which is the center of mass and positive charge, while the negatively charged electrons spinning around the nucleus of the atom at a particular energy level (specific trajectory).

Remember:

- Electrons moving around atoms on certain trajectories without removing energy

- Electrons can move from track to track low-level high energy level by absorbing energy and vice versa.

6. Wave mechanics (Louis De Broglie)

Atom is:

- Basic atomic theory, Bohr Rutheford

- Consists of atomic nuclei which is the center of mass and positive charge, while the negatively charged electrons spinning around the nucleus in orbitals

- Probability of finding electrons moving on a trajectory in various directions is called the orbital

- So at the Rutherford-Bohr theory of atoms contained in the orbital electrons move.