Wiens has a Ph D in Physics, with a minor in Geology.
His Ph D thesis was on isotope ratios in meteorites, including surface exposure dating.
A radioactive element is one with an unstable nucleus, which radiates alpha, beta or gamma radiation and gets converted to a stable element.
This article has a comprehensive list of radioactive elements and their properties.
Thus, The mass of protons and neutrons have approximately same, hence the atomic mass of an atom is equal to A.
On the basis of atomic number and mass number, elements can be classified as isotopes, isobars and isotones.
Has there been any way to express the number of protons in an atom? Protons and neutrons are also known as the nucleons.
All atoms have a certain value of mass number which is derived as follows.Hence, the sum of number of proton and neutron is known as mass number.The number of neutrons, N, is known as the number of neutrons in an atom.The name 'radioactive' may suggest to you that radioactive elements radiate radio waves, but unfortunately that is not so!The name 'radioactivity' is a misnomer because these elements have nothing to do with radio waves! To understand radioactivity, we need to explore the structure of an atomic nucleus.