Which of these will have a molecule as the smallest particle? (there are three) copper, Cu
phosphorus, P.
iron, Fe
nitrogen, N2
calcium, Ca
sulfur, S.
lithium, Li

Chemistry worksheet - i am not sure what they are asking for exactly?

The bohr model of the atom explained why emission spectra are discrete. it could also be used to explain the photoelectric effect. which is a correct explanation of the photoelectric effect according to the model?

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.