How many meta states does the first isotope to be synthesized in Am in 1944 have?
Isotopes of americium Americium (Am) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no known stable isotopes. The first isotope to be synthesized was Am in 1944. The artificial element decays into alpha particles. Americium has an atomic number of 95 (the number of protons in the nucleus of the americium atom).
Isotopes of silicon Silicon (Si) has 25 known isotopes, with mass numbers ranging from 22 to 45. Si (the most abundant isotope, at 92.23%), Si (4.67%), and Si (3.1%) are stable. The longest-lived radioisotope is Si, which is produced by cosmic ray spallation of argon. Its half-life has been determined to be approximately 150 years (0.21 MeV), and it decays by beta emission to P (which has a 14.28 day half-life ) and then to S. After Si, Si has the second longest half-life at 157.3 minutes. All others have half-lives under 7 seconds. The least stable is usually Si with a half-life greater than 60 nanoseconds.