Models of the Atom

Many scientific advances have continued to change the model of the atom. In 1926, Erwin Schrˆdinger, an Austrian physicist, took the Bohr atomic model one step further. Schrˆdinger used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the Quantum Mechanical model of the atom. Unlike the Bohr model, which defines the exact path of an electron, the Quantum Mechanical model predicts the probability of the electron's location. This model can be represented as a nucleus surrounded by an electron cloud. The probability of finding the electron is greatest where the cloud is most dense and least likely in a less dense area of the cloud. Until 1932, the atom was believed to be composed of a positively charged nucleus surrounded by negatively charged electrons. In 1932, James Chadwick discovered the neutron, an uncharged particle contained in the nucleus. Since then, through continued experimentation, more particles have been discovered in the atom. Quarks are believed to be even smaller units than protons and neutrons. In turn, quarks are made up of vibrating strings of energy. The search to find even smaller particles that make up an atom continues.