One radioactive isotope of calcium has an atomic mass number of 47. how many neutrons are in the calcium-47 nucleus?

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Acompound has a molecular weight of 12.124 atomic mass units and the empirical formula c3h40. what is the molecular formula of the compound?

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?