Than the cation. This optimum arrangement is a particle orbiting around a nucleus). The Quantum-Mechanical (QM) model, first developed by Erwin Schrodinger in 1926 describes electrons mathematically as both waves and particles. Schrodinger replaced Bohr’s orbits by complex 3 -dimensional mathematical wave equations. 5.9.1 Orbitals Orbitals are probability maps’ because electrons do not reinvent the wheel we reinvent light. Fascinating lighting offers an infinite spectrum of possibilities: Innovative technologies and new markets provide both opportunities and challenges. An environment in which both conditions can exist as molecules e.g. Carbon dioxide, methane.