james chadwick discovered that the number of protons for each element’s atoms is unique.
james chadwick discovered that the number of protons for each element’s atoms is unique.
who discovered that the number of protons for each element’s atoms is unique?
james chadwick
on hearing of the paris results, neither rutherford nor james chadwick at the cavendish laboratory believed the gamma ray hypothesis. assisted by norman feather, chadwick quickly performed a series of experiments showing that the gamma ray hypothesis was untenable. the previous year, chadwick, j.e.r. constable, and e.c. pollard had already conducted experiments on disintegrating light elements using alpha radiation from polonium. they had also developed more accurate and efficient methods for detecting, counting, and recording the ejected protons. chadwick repeated the creation of the radiation using beryllium and aimed the radiation at paraffin following the paris experiment. paraffin wax is a hydrocarbon high in hydrogen content, hence offers a target dense with protons; since neutrons and protons have almost equal mass, protons scatter energetically from neutrons. chadwick measured the range of these protons, and also measured how the new radiation impacted the atoms of various gases. he found that the new radiation consisted of not gamma rays, but uncharged particles with about the same mass as the proton. these particles were neutrons. chadwick won the nobel prize in physics in 1935 for this discovery.
discovery of the neutron
a chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol "z". the mass number is the sum of the number of protons and neutrons in a nucleus. although all the nuclei of all atoms belonging to one element will have the same atomic number, they may not necessarily have the same mass number; atoms of an element which have different mass numbers are known as isotopes. for example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbon, but atoms of carbon may have mass numbers of 12 or 13.
chemistry