Which element has the electron configuration [Ar] 4s² 3d²?

The electron configuration [Ar] 4s² 3d² corresponds to the element titanium (Ti), which has an atomic number of 22. In this configuration, the [Ar] represents the electron configuration of argon, accounting for the first 18 electrons. The remaining 4 electrons that titanium has are distributed in the 4s and 3d sub-levels.

The two electrons in the 4s orbital and the two electrons in the 3d orbital are characteristic of titanium. The 4s sub-level is filled before the 3d regardless of the energies involved due to the specific filling order in the Aufbau principle.

Titanium is located in the fourth period and is a transition metal, classified in group 4 of the periodic table. This arrangement of electrons makes titanium unique in its chemical properties and interactions, especially as it can undergo various oxidation states generally seen in transition metals.

In summary, the specific electron configuration allows us to identify titanium, as the unique distribution of electrons directly correlates to its position in the periodic table and its elemental properties.