Aprincipal quantum number refers to:
the numbered energy levels starting from the nucleus outward
the total energy of an electron
the maximum number of electrons at a given level
the s, p, d, f levels

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

What term is missing from the central region that describes hypotheses, theories, and laws? popular predictable mathematical falsifiable

Which element is the least metallic between cadmium, silver, zinc, or iron?