I believe the correct answer is the second option. There will be two cobalt atoms in one formula unit of cobalt (III) oxide. It has a chemical formula of Co2O3. This compound is does not naturally occur so it is being synthesized. It is mostly used as bleaching agent.
C. rusting is the correct answer
Basic facts about sex and reproduction, as told to a child
Answer:
six noble gases
Here are five of the six noble gases: helium, neon, argon, kypton and xeon. They're all colourless and transparent. Krypton and xeon form compounds only with difficulty. Helium, neon and argon don't form compounds at all.
