13. How many electrons does a complete third electron shell hold?

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87