Among many different early scientists, Antoine Lavoisier was one of the most influential. He discovered that the mass of a substance is maintained in a chemical reaction. The total mass of the products of a chemical reaction is always the same as the total mass of the starting materials consumed in the reaction. His discovery led to the formation of one of the most fundamental rules in chemistry: the Law of Conservation of Mass. This law states that mass of matter remains constant in any chemical reaction, including changing from one form into another, separating or making mixtures, and decomposing pure substances. His breakthrough signified the beginning of modern chemistry. Another important discovery that influenced concept of atoms was Dalton’s Atomic Theory. His finding was influenced by Democritus’s original ideas about the atom. He went further than the Greek philosopher by performing experiments and studying the ratios of how elements combine in chemical reactions. Based off his results, Dalton obtained a number of different concepts, which he assembled into one theory: the Atomic Theory. This theory has five main point and they are all matter is composed of indivisible particles called atoms, all atoms of a particular element are identical, different elements have different atoms, atoms combine in whole-number ratios, and in chemical reaction, …show more content…
Thompson. His name was Ernest Rutherford and he discovered the positively charged particles in the atom, called protons. He discovered them by firing alpha particles at a very thin sheet of gold foil. Alpha particles are quite large and they were traveling at such high speeds in the experiment that Rutherford and his colleagues believed that they would pass right through the foil. This hypothesis was based off J.J. Thompson’s Plum Pudding model of the atom. Since his model suggested that there was a positive charge distributed throughout the atom, Rutherford didn’t think that there would be much interference for the alpha particles and they would pass right through the gold atoms and they would be detected on a screen on the other side. This was not the case. To his surprise, he found that many of the particles scattered and some even deflected right backwards. J.J. Thompson’s original model was then wrong, and it had to be adjusted to fit the new evidence. Rutherford believed that there must be a large, positively charged particle directly in the middle of the atom. He also believed that the electrons must have been revolving around the center particle, instead of being randomly scattered throughout the atom, therefore the atom was mostly empty space. These two major discoveries helped advance other’s knowledge of the atom’s structure and inspired the continuation to improve