A student is trying to distinguish elements from compounds. If a substance is an element, what else must be true about it?

50 pts plz what is the physical state of matter of baking soda.

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

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions