Chemistry & Environmental Dictionary

The time it takes for one-half of the atoms of an unstable element or nuclide to decay radioactively into another element or nuclide The reactive nonmetals that are in Group 17 of the periodic table. All of these elements are electronegative. Any material or substance, which even in normal use, poses a risk to health, safety, property or the environment. Hazardous materials are broken down into nine primary classes by the United Nations, the USDOT, IATA and other regulatory bodies for the...