What is the name given to substances like iron and sulfur, which contain only one type of atom?

In which environment would primary succession occur? a forest with a few remaining trees after a recent wildfire an area of exposed rock after a glacier melts away beach that is exposed to the air at low tide an abandoned baseball field in a small town

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

Which of the following statements best explains why chemistry is testable a) it can measure data by experiments b) it cannot add new evidence c) it cannot be verified d) it is biased