1240C

1240C refers to a specific chemical compound, Carbon-12 isotope with a mass number of 12 and atomic number 6. It is the most common and stable isotope of carbon. This isotope is fundamental to the definition of the mole, a unit of measurement in chemistry. The atomic mass unit is defined as one-twelfth the mass of a free atom of carbon-12 in its ground state. Carbon-12 constitutes approximately 98.9% of all naturally occurring carbon on Earth. Its nucleus consists of six protons and six neutrons. The relative abundance and stability of carbon-12 make it a crucial reference point for atomic masses and isotopic analysis. It is not radioactive and does not undergo decay. The designation "1240C" is a shorthand notation, with "12" indicating the mass number and "C" representing the element carbon.