Calcium is a metal in group IIA of the periodic table with atomic number 20, an atomic weight of 40.08, and a density of 1.55 Mg/m 3. Its melting point is 838 C, and it boils at 1440 C. The electronic ...

and so electrons go into the 4s orbital before occupying the 3d orbitals. Consequently, potassium and calcium have the following electon configurations. Writing out all the orbitals can be a bit ...