What is the principal quantum number for the last electron that is
added to potassium?

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.

Nan element’s square on the periodic table, the number with the greatest numerical value represents the

In a ball-and-stick molecular model, what do the sticks represent?