He also assumed that the electrons were located outside the nucleus. * 1922: Nielsen Boor established his theory that the electrons travel in distinct orbits around the atom’s nucleus. * 1926: Erwin Schrodinger stated his development of the mathematical description that described the ways that electrons would follow in their orbits around the nucleus. * 1932: James Chadwick discovered the neutron that Is no charge (neutral). He also found the neutron weighted slightly heavier than the proton. 1939: Lisa Emitter published the first paper about nuclear fission.
She predicted the existence of chain reaction, which contributed to the development of the atomic bomb later. * 1941: J Robert Oppenheim was known as the “father of the nuclear bomb” after he was brought into the atomic bomb project of the US government. One year later he gathered the group of some of the best physicists in the country to discuss the design of the actual atomic bomb. , John Dalton proposed his atomic theory in which he stated that elements insisted of tiny particles called atoms.
He also stated that the atom was simple, solid, and Impenetrable and bond together In a specific proportion. He also said the reason elements differed from others was that atoms of each elements were different from one another, means that they have different masses. He also proposed these 4 theories that combined with the one above to make up what he called the “Modern Atomic Theory“. 1. Atoms could not be created or destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together. . Atoms were indivisible. . All atoms were identical and they have the same mass. 4. Compounds Included atoms of different elements combined together. The truth of Modern Atomic Theory: * Atoms were not indivisible. That was proven by Marie Curie and many others scientists In later years. * All atoms off given element are Identical Is not perfectly true, as today understanding know that different Isotopes of an element have slightly different weights. An Atom is now known as the smallest part of an element which can appear in a Heimlich reaction.
The atom consists of three main particles, 1. The Proton which has mass of approximately 1 atomic mass unit and a positive charge. 2. The Neutron which has a mass of approximately 1 atomic mass unit and no charge. 3. The Electron which has a mass 1/1840 of the proton and a negative charge. 4. Current model based on quantum theory 5. Electrons exist in probability clouds called orbital 6. Electrons do NOT orbit nucleus in circular pattern Sources: http://www. USC. IEEE/academic http://del. Clacks. Deed http://en. Wisped. Org