J.J. Thomson's atomic atomic model was called the Plum Pudding Atomic Model, and it was based on the idea that electrons are negatively charged particles scattered through out the positively charged atom. While Thomson was right about the existence of electrons, he was wrong on where they are located within the atom.Know More
Thomson compared the way that the electrons are scattered throughout the atom to the raisins of a plum pudding. This theory suggested that the negative and positive charges in the atom existed in the same sphere of existence, but it wasn't until 1911 that the location of the nucleus that housed these charges was discovered. The man who discovered the nucleus, Ernest Rutherford, was a student of Thomson at one time and was actually testing Thomson's theory when he made his own discovery: rather than being scattered throughout the atom, electrons orbit a positively charged nucleus. Once Rutherford had discovered that particles in foil were able to deflect the H2+ particles in 1911, the plum pudding model was set aside for Rutherford's model. Thomson also abandoned his own model to support Rutherford's model.
Throughout Thomson's career, he held a number of distinguished positions due to his discoveries. He was given a knighthood in 1908 by the British Royal family in addition to a Nobel Prize in 1906. Even though Thomson's plum pudding theory was disproved, many of the elements of his discoveries such as electrons were key to finding and building the model that is used currently.Learn more about Chemistry
The idea of electron shells was developed by Niels Bohr in his 1913 model of the atom, which places electrons into stable orbits around the nucleus. The Bohr model was a modification of the Rutherford model, which did not require that electrons move in orbits of fixed size and energy.Full Answer >
Although the early Greek philosopher Democritus hypothesized the existence of atoms, it was not until the late 1800s that English physician J.J. Thomson proposed a model for the atom. J.J. Thomson discovered the atom because of his discovery of the electron, which was a very significant discovery in the field of physics.Full Answer >
Each atom contains an equal number of protons and electrons; these particles will be equal in value to an element's atomic number. For example, the element gold, or AU, has an atomic number of 79, meaning it has 79 protons and 79 electrons. Atomic number is not to be confused with atomic mass.Full Answer >
Helium is an element of the periodic table that is composed of subatomic particles including protons, neutrons and electrons. The atomic number of helium is 2, which means it contains two protons and two electrons. The most common isotope of helium contains two neutrons.Full Answer >