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He made an Atomic Theory for the cosmos and it is very similar to our current understanding of the atomic theory. He laid the basis for our modern atomic theory. -
The Law of Conservation of Mass says that nothing can be created or destroyed in chemical reactions. This is significant because it lays the foundations for modern chemistry. -
This law states that any chemical compound has a fixed ratio of its parts, and that the compound does depend on any method of preparation. -
This law was proposed by Dalton and means that the ratio of the masses of the second element that combine with one gram of the first element can always be reduced to small whole numbers. This is significant because it was helped Dalton's argument about atoms being indestructible, but is also a strong foundation that was needed for chemistry to flourish and become what it is today. -
Dalton established that all atoms are different from one another. Dalton’s measurements and real world data for his theory was wrong, but the foundation of what his theory was built off of was right. -
Dalton's Atomic theory states that all matter is made up of atoms, that atoms are indistructible and indivisible, all atoms of the same element share identical properties, atoms from different elements have differernt mass, and all compounds are made up of a whole number ratio of atoms. This furthered our knowledge of atomic theory by laying a strong foundation. He may have gotten some things wrong, but he got what matters right. -
Mendeleev created the periodic table. This was a very useful tool as it classified all the elements in a way that was easy to understand. -
Becquerel discovered that x - rays were not the only waves/particles radiating from uranium. -
Thomson put two oppositely charged plates on either side of the cathod ray. The particles from the ray were repelled by the negatively charged plate and they were attracted by the positively charged plate. He then tried it with magnets and got the same results. He worked out the mass to charge ratio with this and it was smaller than any other known atom. This led him to propose that the particle is negatively charged and must be part of the atom because of it's mass. -
Thomson discovered the electron by observing Cathode Rays. This is significant because it revolutionized the atomic model and led to another evolution of it. With this data J.J. Thomson made the Plum Pudding model which is significant because it changed into the Rutherford Model. -
Marie Curie discovered the elements Radium and Polonium. She also invented methods for seperating radium from radioactive substances in sufficient quantities. Her contribution to the atomic theory was that she found that radiation was caused by the atom itself instead of the structure of the material. -
The Plum Pudding Atomic Model was a theoretical model proposed by J.J. Thomson based off of their limited knowledge of atoms. This model is significant because it gave a starting point for the atomic model to build off on. -
Robert Millikan found the exact electrical charge found in a electron. -
Rutherford discovered how to split an atom which paved the way for nuclear fission, and he also contributed to the periodic table. -
This experiment involved shooting alpha particles at a thin sheet of gold. The exptected results were all the alpha particles would pass through the gold with little or no deflection. The actual results were that most of the particles pass through the gold with no deflection, but about 1/8000 of the atoms were deflected at large angles. This experiment showed us that atoms were mostly empty space, but the center had a strong positive charge and most of the mass of the atom. -
The Rutherford Model was created after the Gold Foil Experiment was conducted. The experiment showed that the old model was very inaccurate, so Rutherford created the Rutherford Model which describes the results of the Gold Foil Experiment. The Rutherford Model shows the atom to be composed of a nucleas which includes protons and neutrons. The electrons of the atom orbit the nucleas. This model is significant because it largely is still correct. -
Bohr contributed to the atomic theory by making the Bohr atomic model and his inclusion of quantums in it. -
The oil drop experiment calculated the charge of a single electron by ionizing oil droplets. After that they measure the mass and the charge it takes to resist gravity's influence. From doing this hundreds of times over, they found the exact electrical charge of a electron. This is significant because it the base unit of measurement for electricity and it helps us make a more accurate model of the atom. -
This model combined Rutherford's Atomic Model and the quantum. It describes electrons as having stationary states that they travel between, and only when they travel is energy released or used. -
Schrodinger theorized that the behavior of electrons can be explained by treating them like waves. He also formulated a wave equation that could accurately calculate the energy in the electrons of atoms. -
This model describes how electromagnetic radiation behaves as a wave and a particle. It also goes into further detail about the locations and energies of electrons. This is significant because it is very detailed. -
Chadwick discovered the existence of neutrons, and this discovery allowed the fission of Uranium 235. -
Gell-Mann discovered the existence of quarks and gluons. This showed us that there are smaller particles than subatomic particles. This led to the fields of Quantum Chromodynamics.