Page 14 - GALIET PHYSICS BLOSSOMS IV+

WHY ENERGY DECREASES AND HOW CHEMICAL BONDING OCCURS5
• Before they come together, each atom has two electrons bound to the He nucleus (2 protons + 2 neutrons) by a strong electrostatic attraction causing a single
potential well as shown above, which is very narrow given that the radius of the H atom is so small. So, small radius, small potential well.
• However, when we bring 10 He nuclei close together, we get a 20 well potential formed by the 20 joined protons. So, larger radius, larger potential well.
• Moreover, the ground state of 20 electrons differs in shape from the ground state of 2 electrons. It is larger and spread out because it conjugates 10 nuclei.
• Each of the 20 proton-bound electrons spread their clouds over the 20 potential wells.
• When their clouds spread, they lower their energy immensely given that (1) spreading means lowering of energy, and (2) compressing means increase of energy.
• It is as if a new electron cloud joined the clouds of each of the 10 isolated atoms, bonding them chemically in this way.
• Indeed, when part of the 20 electron clouds spread out amongst the 20 protons, they “screen” their natural repulsive force (Coulomb’s like charges, repel; in this case ++ repel). When the electron clouds spread out and surround the protons, their energies are lowered, it gets foggy, and the protons are blinded. Consequently, they cannot see their own repulsive forces. Instead, what protons see in their midst, are flirting electron clouds, so they feel a deep attraction or bond towards them (Coulomb’s unlike charges attract; in this case +-).
• This process where electrons lower their energy by spreading out to link different atoms is essential to chemical bonding! Without, we could not comprehend how a gathering of protons could bond instead of naturally repel each other! Indeed, in order to spread out and lower its energy as much as possible, the electron’s wave adapts itself by the superposition of different states.
5 Dr. Stamp. From class lecture notes and from Basic Ideas of Quantum Mechanics. I. Quantum States. 16-17. •14•