In the symbol 42he, the subscript 2 is the for helium and the superscript 4 is the for helium. atomic mass; atomic number atomic number; atomic mass mass number; atomic number atomic number; mass number

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.