Multnomah County /mÉltËnoÊmÉ/ is one of 36 counties in the U.S. state of Oregon. As of the 2010 census, the county's population was 735,334, making it the most populous county in Oregon. Its county seat, Portland, is the state's largest city. Multnomah County is part of the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area, and though smallest in area, it is the state's most populous county.
Nucleons are either protons or neutrons and the total number of nucleons is given the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and given the symbol Z.Protons and neutrons have a mass of 1, protons are positively charged and neutrons have no charge. 1  A (mass number): total number of nucleons = protons + neutrons.2  Z (atomic number): number of protons. great many different configurations of the nucleus may occur. In each case, the atomic number defines the element, i.e. it is the number of protons that determines that carbon (having 6 protons) is carbon.
In the case of iodine-131 (131 I), the atomic number Z (number of protons) is 53 and number of neutrons is 78. So the total mass number is 131. An unstable nuclide tries to attain stability through radioactive decay releasing alpha, beta and gamma rays. In medicine, this radiation is used for diagnosis and treatment.