What is a successful outcome for using a scientific method?

Which is an example of a highly unstable isotope that is often used in fission reactions?

How many grams of oxygen gas will react completely with a block of calcium metal that is 3.0 cm by 3.5 cm by 4.2 cm, if the density of calcium is 1.55 g/ml? show all steps of your calculation as well as the final answer.

Amodel of an atom is shown below. which element is represented by this model of an atom? boron, carbon, neon, or sodium?