Atomic and nuclear tests can involve many hazards. It produced plutonium for use in cold war atomic bombs. See Linear combination of atomic orbitals molecular orbital method. Relative atomic and molecular mass values as defined are dimensionless. Superfortress aircraft capable of delivering atomic bombs. It is used as a shielding gas in welding methods such as atomic hydrogen welding. Plumbane may be obtained in a reaction between metallic lead and atomic hydrogen. Landau led a team of mathematicians supporting Soviet atomic and hydrogen bomb development. Mercury is a chemical element with the symbol Hg and atomic number 80. Phosphorus is a chemical element with the symbol P and atomic number 15. Nitrogen is the chemical element with the symbol N and atomic number 7. Molybdenum is a chemical element with the symbol Mo and atomic number 42. Chlorine is a chemical element with the symbol Cl and atomic number 17. Protons and neutrons are baryons, joined by gluons to form the atomic nucleus. Zinc is a chemical element with the symbol Zn and atomic number 30.