Electronic configuration of Potassium (K)
Atomic number of potassium = 19
Therefore number of electrons = 19
Since, maximum number of electrons in outermost orbit will not be more than 8, thus the 19th electron of potassium atom will reside in 4th orbit.
Thus, electronic configuration of potassium is
Number of orbit in potassium = 4
Electronic configuration of Calcium (Ca)
Atomic number of calcium = 20
Therefore number of electrons = 20
Thus, electronic configuration of calcium is
Number of orbit in calcium = 4