This is an easy quiz and I will do brainiest. its one question please help ASAP

Why do sodium and neon have vastly different chemical and physical properties despite having similar atomic masses?

What’s the percent by mass of carbon in c10h14n2

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.)