Other Structures with amaximum e8%883 c40 The el as9neaaaweg 一 c s-Ay 5 5 Other examples of resonance: Not all resonance forms are equal. 1. Structures with a maximum of octets are most important. 2. Charges should be preferentially located on atoms with compatible electronegativity. If this conflicts with rule 1, then rule 1 takes precedence. 3. Structures with less separation of opposite charges are more important resonance contributors than those with more charge separation. In some cases charge separation is necessary and guideline 1 takes precedence over guideline 2: If there are two or more charge separated resonance structures which comply with the octet rule, the most favorable one places the charges on atoms of compatible electronegativity: Atomic Orbitals: A Quantum Mechanical Description of Electrons around the Nucleus 1-6 The electron is described by wave equations. An electron within an atom can have only certain definite energies called energy states. Moving particles such as electrons exhibit a wavelength determined by the de Broglie relation: h λ= mv Where h is Plank’s constant, m is the mass of the electron in kg, and v is the velocity of the electron in m/s. The electron waves contain nodes, where the amplitude of the wave changes sign, and can interact with each other, producing either constructive or destructive interference: The wave theory of electron motion is called quantum mechanics. The quantum mechanical equations describing the motion of the electrons are called wave equations. The solutions of these equations are called wave functions and are represented by the Greek letter, ψ. The square of the wave function, evaluated at a point in space (x,y,z) represents the probability of finding the electron at that point at any given time. Each wave function corresponds to a specific discrete energy and the system is said to be quantized