Transition elements + ligands = colorful complexes! 🌈

• Transition Elements: These are the awesome elements that form beautiful coloured compounds when they hang out with ligands!
• Ligands: Think of them as the ultimate fan club for transition elements. They’re molecules or ions eager to give their lone pair of electrons to a transition element cation. Imagine giving your favorite singer a rose during a concert! 🌹

📌 Key Concept: The bond between a ligand and the transition element cation is called a coordination bond.

• All five d orbitals of transition elements usually have the same energy. We call them 'degenerate'. But when ligands come into play, it's like a talent show where the d orbitals split into two groups with different skills (or energies).
• When light shines on this complex, electrons from the lower energy orbitals get excited and jump to the higher ones. This is like jumping on a trampoline. Weeeee!
• The color we see is the opposite of the color absorbed by the complex. So, if our complex absorbs blue, we'll see orange! This is based on the color wheel (just like the one artists use). 🎨

Example Time!: The [Cr(H₂O)₆] ₃+ complex is like a rock star that loves yellow light. When it absorbs yellow, it shines in violet, just like a rock concert with cool lighting!

The bigger the gap between the orbitals, the more energy an electron needs to make the jump. This is like jumping from a taller trampoline. The formulae that rock this world:

• Speed of Light 🚀: c = f × λ
• Energy 🎸: E = Planck' sconstant × frequency