What is the period number in which helium is found?

What are the percent by mass of copper in penny lab

Water molecules have a strong attraction to each other because of hydrogen bonding, allowing water to move against gravity up a plant's stem through capillary action. true false

Which of the following describes a compound? (hint: carbon and oxygen bo a. a piece of pure carbon, containing only carbon atoms b. oxygen gas surrounding a solid piece of carbon c. a substance made of two oxygen atoms for each carbon atom carbon and oxygen atoms mixed without being bonded together