* Valence shell in chemistry

# REDIRECT Electron shell # Valence shells

* Valence shell

Valence shell electron pair repulsion ( VSEPR ) rules are a model in chemistry used to predict the shape of individual molecules based upon the extent of electron-pair electrostatic repulsion.

* Chemistry: Molecular theory — Kinetic theory of gases — Molecular orbital theory — Valence bond theory — Transition state theory — RRKM theory — Chemical graph theory — Flory-Huggins solution theory — Marcus theory — Lewis theory ( successor to Brønsted – Lowry acid – base theory ) — HSAB theory — Debye – Hückel theory — Thermodynamic theory of polymer elasticity — Reptation theory — Polymer field theory — Møller – Plesset perturbation theory — Density Functional Theory — Frontier molecular orbital theory — Polyhedral skeletal electron pair theory — Baeyer strain theory — Quantum theory of atoms in molecules — Collision theory — Ligand field theory ( successor to Crystal field theory ) — Variational Transition State Theory — Benson group increment theory — Specific ion interaction theory

* Valence electron

Valence bond theory now complements molecular orbital ( MO ) theory, which does not adhere to the VB idea that electron pairs are localized between two specific atoms in a molecule but that they are distributed in sets of molecular orbitals which can extend over the entire molecule.

# REDIRECT Valence electron

# REDIRECT Valence electron

The Quantized Valence Bonds ' Molecular Mechanics ( QVBMM ) force field ( implemented in Exorga, Incorporated's StruMM3D product, once named STR3DI32 ) is unique in molecular mechanics as the only one to directly use all lone pair interactions in all of its energy calculations.

The number of electrons in each element's electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior.

The energy necessary to remove an electron from its shell ( taking it to infinity ) is called the binding energy.

All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell ; lawrencium, a d-block element, is also generally considered an actinide.

Upon ejection the kinetic energy of the Auger electron corresponds to the difference between the energy of the initial electronic transition and the ionization energy for the electron shell from which the Auger electron was ejected.

This transition is accompanied by a 12 % volume decrease and delocalization of the electrons at the 5f electron shell.

In 1916, chemist Gilbert N. Lewis developed the concept of the electron-pair bond, in which two atoms may share one to six electrons, thus forming the single electron bond, a single bond, a double bond, or a triple bond ; in Lewis's own words, " An electron may form a part of the shell of two different atoms and cannot be said to belong to either one exclusively.

He introduced the Lewis notation or electron dot notation or Lewis dot structure in which valence electrons ( those in the outer shell ) are represented as dots around the atomic symbols.

* Electron configurations of the elements ( data page ) — electron configuration, electrons per shell

Some properties of europium are strongly influenced by its half-filled electron shell.

However in materials with a filled electron shell, the total dipole moment of the electrons is zero because the spins are in up / down pairs.

All but one of the lanthanides are f-block elements, corresponding to the filling of the 4f electron shell ; lutetium, a d-block element, is also generally considered to be a lanthanide due to its chemical similarities with the other fourteen.

Indeed, even if the photoelectric effect is the favoured reaction for a particular single-photon bound-electron interaction, the result is also subject to statistical processes and is not guaranteed, albeit the photon has certainly disappeared and a bound electron has been excited ( usually K or L shell electrons at nuclear ( gamma ray ) energies ).

He found an essential clue in a 1924 paper by Edmund C. Stoner which pointed out that for a given value of the principal quantum number ( n ), the number of energy levels of a single electron in the alkali metal spectra in an external magnetic field, where all degenerate energy levels are separated, is equal to the number of electrons in the closed shell of the noble gases for the same value of n. This led Pauli to realize that the complicated numbers of electrons in closed shells can be reduced to the simple rule of one per state, if the electron states are defined using four quantum numbers.

One particularly important consequence of the principle is the elaborate electron shell structure of atoms and the way atoms share electrons, explaining the variety of chemical elements and their chemical combinations.

Most often, this occurs when an electron is stripped ( or " knocked out ") from an electron shell, which leaves the atom with a net positive charge.

The chemical properties of rutherfordium were based on calculation which indicated that the relativistic effects on the electron shell might be strong enough that the p orbitals have a lower energy level than the d orbitals, therefore making the element behave more like lead.

These absorptions and emissions, often referred to as atomic spectral lines, are due to electronic transitions of an outer shell electron to an excited state.

In massive stars, the core is already large enough at the onset of hydrogen burning shell that helium ignition will occur before electron degeneracy pressure has a chance to become prevalent.

Characteristic X-rays are emitted when the electron beam removes an inner shell electron from the sample, causing a higher-energy electron to fill the shell and release energy.

After taking a small sample of the outer shell, the three hear a pair of voices, which informs them that the egg belongs to Mothra.

The trop shell consists of three people where the bow has a pair of sculling oars, and 2, 3 each a sweeping oar.

Twin BNC ( also known as twinax ) connectors use the same bayonet latching shell as an ordinary BNC connector but contain two independent contact points ( one male and one female ), allowing the connection of a 78 ohm or 95 ohm shielded differential pair such as RG-108A.

The six outer shell electrons of each oxygen atom are shown in black ; one electron pair is shared ( middle ); the unpaired electron is shown in the upper left and the additional electron conferring a negative charge is shown in red.

The earliest known masonry double shell domes are those of a pair of brick tower tombs from the 11th century in Kharraqan, Iran.

The tomb itself contained the remains of an adult male that was interred with a jade and shell necklace, a pair of jade earflares, two shell disks, a pair of pearls, five pottery vessels, and fifty-nine valves of Spondylus shell.

The weapon consisted of a modified standard 500 kg bomb called SZ, with a thin metal shell and a high explosive charge inside, equipped with a rocket engine under the bomb, a pair of wings, and an 18-frequency-capability Strassburg radio receiver, named for the 1st century BCE-founded city on the French / German border, getting its signals from a Kehl transmitting set ( named for a German suburb of the two-millennia-old city ) in the carrier aircraft.

The need for a quick replace battery didn't take long to show itself and the rechargeable was replaced with a pair of AA batteries along with a plastic shell encasing the detector.

As the bonding pair is shared between the two atoms, the atom that originally had the lone pair still has an octet ; the other atom now has two more electrons in its valence shell.

During the doratopsis stage, the paralarval chiroteuthids possess a greatly elongated gladius ( internal shell ) extending well beyond the fins ; this supports a long, trailing tail-like structure that is further adorned with — depending on the species — either a pair of large oval or heart-shaped " secondary fins ", a series of small flaps running the length of the tail, or a series of oval " bulbs " made buoyant by low-density fluids.

The pair of small rounded flaps form the parapodial cavity over the mantle cavity and the vestigial shell.

** Description: headshield with a pair of fleshy lobes ; thin operculum ; white shell with orange-brown markings at the base and at the apex ; large body whorl ; large columella, slightly twisted ; shell sculptured with grooves

*** Description: black sea slug with yellow warts on a white background ; the mantle encloses the bubble-shaped fragile shell ; there is a pair of enrolled rhinophores on the head ; the eyes are the two black spots on the head, just in front of the shell ;

Other scenes show the birth of Aphrodite, often raised in a conch shell by a pair of sea centaurs, and accompanied by fishing Erotes ( winged love gods ).

They are crustaceans with five pairs of legs, the first pair modified to form a pair of pincers, a flattish shell, and a short, broad abdomen folded under its thorax.