Skip to main content
Like
Create new Glog
previous
next
Email share
945 views | 0 likes | 0 reposts
Bohr Model (1913)
Rutherford Model (1911)
Thomson Model (1903)
Dalton Model (1803-1805)
Democritus Model
Dalton's Atomic Theory -Atoms make up all matter and are not able to be divided or destroyed. -All atoms of the same element have the same proporties. -A compound is formed by two or more atoms of different kinds. -A rearrangement of atoms is a chemical reaction.
Nobel Prize Winners -John Dalton never won the Nobel Prize -Thomson was awarded the nobel prize for physics in 1906. -Rutherford was awarded the Nobel Prize for chemistry in 1908. -Bohr received the Nobel Prize in 1922 for physics. -Heisenberg won the NobelPrize in 1932 in physics.
J.J Thomson was the first to find that the atom contains positive and negative particles. He named the negative particles electrons. Thomson experimented with cathode ray tubes to prove that magnectic forces repelled electrons. Thomson also found that hydrogen atoms only contain one electron.
The Heisenberg Uncertainty Principle states that the speed and position of an object cannot be measured at the exact same time and that the two proporties together have no meaning in nature because the object has to move from its position in order to find the speed.
The element of lead has an atomic mass of 207.2 amu. Lead has an atomic number of 82 which means that each lead atom contains 82 protons and electrons. The difference of the atomic mass and the atomic number is 125 which means that lead has 125 neutrons in each atom.
Isotopes are atoms of the same element that contain the same amount of protons, but different amounts of neutrons. Dalton's atomic theory did not support the existence of isotopes becasue it states that all atoms of the same element have exactly the same proporties.
Aristotle's Ideas: -empty space cannot exist -matter is made of earth, fire, air, and water Aristotle disagreed with Democritus because Aristotle thinks that there is no such thing as empty space and that matter is made of earth, fire, air, and water. Aristotle did not believe in the idea of atoms.
The Gold Foil Experiment (also known as the Geiger-Marsden experiment or the Rutherford experiment): In this experiment, radioactive particles were set on fire on a thin sheet of gold foil. The particles were detected by a thin sheet of zinc sulfite. Rutherford found that most of the particles went through the gold foil, but around 1 in every 8000 would not. He concluded that the atom is mostly made up of empty space.
The three main subatomic particles are protons, neutrons, and electrons. Protons and neutrons are located in the nucleus while the electrons are located outside the nucleus. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. Atoms that are neutral contain the same amount of protons as electrons. To find the amount of neutrons an atom has, the atomic number (number of protons/electrons) is subtracted from the atomic mass.
Democritus's Ideas: -matter is made of atoms which are small particles that move through empty space -atoms are solid, homogeneous, not able to be destroyed, unable to be created, and indivisible -there are different kinds of atoms with different shapes and sizes -proporties of matter are established by the size, shape, and movement of atoms
The Gold Foil Experiment
Bohr's model of the atom is inaccurate because it only shows the spectrum of the element hydrogen. His model does not completely show the chemical manner of atoms. There is also evidence that tells us that electrons in atoms do not move in orbit around the nucleus. Bohr's model is different from the modern model because the modern model is not specific to one element. It refers to all atoms of all elements. The modern model shows different energy levels like Bohr's model, but in the modern model the electrons are not orbiting around the nucleus. Although the Bohr model is incorrect in many ways, middle school and biology students stilll tend to use this model of the atom because it is much simpler than the correct model. Bohr's model conveys a basic understanding of the behavior of atoms that younger students can understand.
Democritus's model of the atom is basically the same as Dalton's model because they both are just a solid spherical shape.
The model of the atom changed dramatically rom Dalton to Thomson because Thomson found that atoms contain positive and negative particles.
The atomic theory changed from Thomson to Rutherford because Rutherford concluded that the atom was made up mostly of empty space.
The atom changed from Rutherford to Bohr because Bohr found that there were different energy levels of the electrons. He hypthesized that the electrons orbited the nucleus.
Technology played a large role in the discovery of the structure of the atom because microscopes and other luxuries helped scientists to look at the atom in much more detail.
