The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

Crucially, the place of an element within the periodic table reflects its electronic configuration which ultimately determines boths its chemical and physical properties. Location = number of valence ...

We find that it is the 4s orbital electrons that are ionised first before the 3d orbitals. We have to conclude that, ironically for the d-block elements, the 4s orbitals are in fact higher in energy ...