Two atoms with the same number of protons but a different number of neutrons are

water is used to store them because it would keep the radiation from getting out in the open and causing harm to the workers

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.