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What exactly is the VSEPR theory? Under the Valence Shell Electron Pair Repulsion (VSEPR) theory, pairs of electrons surrounding the core atom of a molecule or ion are positioned as far away as possible to minimise electron-electron repulsion.
The Main Features of VSEPR theory
- The number of valence shell electron pairs around the core atom determines the form of a molecule.
- Because their electron clouds are negatively charged, pairs of electrons in the valence shell repel one another.
- Electron couples tend to align themselves in space in such a way that they reduce repulsion and so maximise distance between them.
- The valence shell is modelled as a sphere, with electron pairs forming a maximum distance between them on the sphere.
- A multiple bond is handled as if it were a single electron pair, and a multiple bond with two or three electron pairs is treated as a super pair.
- When two or more resonance structures can be used to describe a molecule, the VSEPR nodal can be used for any of them.
Negatively Charged Clouds
Air molecules and water droplets in the atmosphere can separate during a storm. As they swirl about in the clouds, air molecules and suspended water droplets collide. Warmer air and water droplets rise, bringing with them charges. The consequence is a positive charge surplus towards the cloud tops and a negative charge excess in the cloud bottom layers. Furthermore, the temperature of increasing water droplets decreases. The negative charge is carried by the warmer, outer layers of these cooling droplets, making it simpler for those charges to wipe off in collisions.
Charges that are similar repel each other. Negative charges on the Earth’s surface are pushed down by surplus negative charge in the lower layers of clouds. The surface, as well as everything on it—trees, houses, and you!—becomes positively charged as a result. And this is where the real fun begins.
The net positive charge on the surface attracts the negative charges along the bottom of the clouds. Charges begin to flow down towards the ground, zigzagging and branching uncontrollably.
Positive charges are attracted upward when these negatively charged “step leaders” reach the surface. One of the rising “streamers” eventually runs into a step leader. At that point, a single, direct conduit for charge to flow between the ground and the cloud is established. In less than a thousandth of a second, billions of electrical charges pass over it.
The energy contained in the quick travel of a charge in a bolt of lightning is enormous—a typical bolt’s energy could power an ordinary American family for nearly a week. The temperature of the surrounding air rises as a result of all that energy—and it rises so quickly that the heat cannot be dissipated quickly enough. The pressure in this area rises to dangerously high levels, causing a sonic shock wave to spread out in all directions.
The light from a lightning bolt reaches your eyes nearly quickly, but the sound of thunder takes a bit to reach your ears. Sound travels at a (relatively) slow speed of around one mile every five seconds, or about one kilometre every three seconds. You may determine the distance to a lightning bolt by counting the seconds between seeing the light and hearing the thunder—”one Mississippi, two Mississippi”—the distance is around 1 mile for every 5 seconds, or 1 km for every 3 seconds.
Electronic Repulsions
Electron Pair Repulsion – The idea that electron pairs orbiting a central atom will want to stay as far away as possible. The shape of a molecule or a polyatomic ion is predicted using electron pair repulsion.
Cause Of Electronic Repulsion
Two charges travelling in opposite directions repel each other electrostatically, but they also generate two parallel currents that are magnetically attracted to each other. Electrostatic repulsion is reduced by magnetic forces, and the space-charge limit is increased.
- The strongest attraction is between two lone pairs.
- The strongest attraction is between two lone pairs. Repulsion between one lone pair and one bonded pair
- The smallest repulsion occurs between two bonded pairs of electrons, whose size is determined by the EN difference between a centre atom and the neighbouring atoms.
Repulsion Between The Pairs Of Electrons In The Valence Shell
Whether in chemical bonds or as lone pairs, electron pairs repel one other.To reduce repulsions, valence electron pairs are orientated as far apart as possible.
According to this hypothesis, a specific shape is developed to reduce repulsion between electron pairs based on the amount of electron pairs (both bonding pairs and lone pairs) around the centre atom.
Conclusion
The valence-shell electron-pair repulsion (VSEPR) theory argues that whether electron pairs are in bond pairs or lone pairs, they reject one other. To reduce repulsion, electron pairs will spread out as widely as possible.Lone pair electrons repel the most, while bond pair electrons repel the least.
