**Introduction**

When comparing the stability of Sc3 (Scandium) and Sc2 (Scandium(II)), it is important to consider various factors that contribute to their stability. Stability refers to the ability of a compound or element to resist decomposition or chemical changes under specific conditions. In this context, we will discuss why Sc3 is generally considered more stable than Sc2.

**Electronic Configuration**

One of the key factors determining the stability of an element or compound is its electronic configuration. Scandium has an atomic number of 21, and its electronic configuration is [Ar] 3d¹⁰ 4s² 4p⁶ 5s² 5p⁶ 4d¹ 5p¹, where the valence shell contains only one electron. In Sc2, two electrons are added to the valence shell, resulting in a configuration of [Ar] 3d¹⁰ 4s² 4p⁶ 5s² 5p⁶ 4d¹ 5p².

**Ionic Stability**

Ionic stability refers to the tendency of an ion to remain intact in a compound. Scandium in its +3 oxidation state (Sc3+) forms stable compounds due to the complete filling of its 3d orbitals. The 3d¹⁰ configuration provides a greater degree of stability compared to the 3d⁹ configuration of Scandium(II) (Sc2+). The half-filled and fully-filled electron configurations tend to be more stable due to the exchange energy and electron-electron repulsion effects.

**Ligand Field Stabilization Energy (LFSE)**

LFSE is a measure of the stability gained by an ion or atom due to the interaction with ligands in a complex. Sc3+ has a higher LFSE compared to Sc2+ due to the presence of one less electron in its valence shell. The lower electron density in Sc3+ results in a stronger interaction with ligands, leading to increased stability.

**Oxidation State Stability**

Scandium predominantly exhibits a +3 oxidation state in various compounds, while Scandium(II) is relatively rare. The +3 oxidation state is more stable for scandium due to the electronic configuration and the greater energy required to remove additional electrons.

**Conclusion**

In conclusion, Sc3 is generally more stable than Sc2 due to its electronic configuration, ionic stability, ligand field stabilization energy, and oxidation state stability. The complete filling of the 3d orbitals in Sc3+ contributes to its greater stability compared to the partially filled 3d orbitals in Sc2+. Additionally, the +3 oxidation state is more common and stable for scandium. These factors collectively contribute to the enhanced stability of Sc3 over Sc2.