Is it true that the most reactive metals are quite plentiful in the Earth's crust?​

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

What is happening when the water inside a kettle heats up and begins to boil

What is a number added in front of a formula in order to balance the equation