Answer:
Potassium has one valence electron.
Potassium has 18 core electron.
Explanation:
Valance electron:
Valence electron is a electron present in the outermost shell of the atom. Potassium electron has 19 electrons. The outermost shell of potassium has only one electron present in it. Thus, Potassium has one valence electron.
Core electrons:
Core electrons are present in the inner shell of atom and it is given by,
Number of core electron = Atomic number - Number of valence electron
Number of core electron = 19 - 1
Number of core electron = 18
Thus, Potassium has 18 core electron.