# data[].attributes.body
This particle became known as the neutron. With the discovery of the neutron, an adequate model of the atom became available to chemists.

# data[].attributes.body
Dalton envisioned atoms as solid, hard spheres, like billiard balls. He utilized wooden balls to model them.

# data[].attributes.body
Schrödinger stated that electrons do not move in set paths around the nucleus, but in waves. It is impossible to know the exact location of the electrons. Instead, we have "Clouds of Probability" called orbitals, which we are more likely to find an electron.

# data[].attributes.body
1. Electrons orbit the nucleus in orbits that have a set size and energy.
2. The lower the energy of the electron, the lower the orbit. 3. This means that as electrons fill up the orbitals, they will fill the lower energy level first.
4. If that energy level is fill (or at capacity), a new energy level will begin.
5. Radiation is when an electron moves from one level to another.

# data[].attributes.body
1. The nucleus of the atom is a dense mass of positively charged particles.
2. The electrons orbit the nucleus
3. Rutherford stated that the atom was like a mini solar system and that the electrons orbited the nucleus in a wide orbit. That is why it is known as the planetary model.

# data[].attributes.body
In the "Gold Foil" experiment, he fired positively charged alpha particles at a gold foil. After measuring the deflection of the particles, most of the particles did not deflect at all. Every now and then a particle would deflect all the way back. From this, he believed that there must be a positive center of the foil. He then called this center the nucleus.

# data[].attributes.body
Using what he had discovered, Thomson predicted what an atom should look like.
1. Because of its design this model is known as the plum pudding model
2. Each atom is a sphere filled with positively charged ‘fluid’. This resembles the sticky jam part of a pudding.
3. Corpuscles (later called electrons), are the negatively charged particles suspended in this ‘fluid’. This resembles the plums in the pudding.

# data[].attributes.body
His atomic theory consists of three basic ideas:
1. All substances consists of atoms which are the smallest particles of matter. They cannot be divided into smaller particles, created, or destroyed.

2. Elements are characterized by the weight of their atoms
3. When elements react, it is their atoms that have combined to form new compounds.

# data[].attributes.body
He called this the theory of the universe: All matter consists of atoms, which are bits of matter too small to be seen.

# data[].attributes.body
Until 1932, the atom was believed to be composed of a positively charged nucleus surrounded by negatively charged electrons. In 1932, James Chadwick bombarded beryllium atoms with alpha particles which produced an unknown radiation. Chadwick interpreted this radiation as being composed of particles with a neutral electrical charge and the approximate mass of a proton.

# data[].attributes.body
Erwin Schrödinger was a revolutionary physicist who used Heisenberg’s uncertainty principle to come up with the atomic model that we still use today.

# data[].attributes.body
Niels Bohr agreed with the planetary model of the atom, but also knew that it had a few flaws. Using his knowledge of energy and quantum physics he was able to perfect Rutherford’s model. He was able to answer why the electrons did not collapse into the nucleus.

# data[].attributes.body
Ernest Rutherford was not convinced about the model of the atom proposed by Thomson. He thus set up the Gold Foil Experiment.

# data[].attributes.body
J.J Thomson was a physicist who is known for discovering the electron. He used his research on cathode ray tube technology in this discovery. Thomson found that this charge was 1000 times lighter that a hydrogen atom. He stated that this negative charge must be inside an atom, and was later known as the electron.

# data[].attributes.body
John Dalton reconstructed Democritus’ theory into the first modern atomic model.

# data[].attributes.body
Democritus was a Greek philosopher who originated the term atom (atomos: meaning indivisible). He believed that if a piece of matter was divided continuously, it will eventually come to a point where you could not divide it further. This fundamental was what Democritus called an atom.