Core electrons are the electrons in an atom that are not valence electrons and do not participate in chemical bonding.[1] The nucleus and the core electrons of an atom form the atomic core. Core electrons are tightly bound to the nucleus. Therefore, unlike valence electrons, core electrons play a secondary role in chemical bonding and reactions by screening the positive charge of the atomic nucleus from the valence electrons.[2]
The number of valence electrons of an element can be determined by the periodic table group of the element (see valence electron):
For main-group elements, the number of valence electrons ranges from 1 to 8 (ns and np orbitals).
For transition metals, the number of valence electrons ranges from 3 to 12 (ns and (n−1)d orbitals).
For lanthanides and actinides, the number of valence electrons ranges from 3 to 16 (ns, (n−2)f and (n−1)d orbitals).
All other non-valence electrons for an atom of that element are considered core electrons.
^Rassolov, Vitaly A.; Pople, John A.; Redfern, Paul C.; Curtiss, Larry A. (2001-12-28). "The definition of core electrons". Chemical Physics Letters. 350 (5–6): 573–576. Bibcode:2001CPL...350..573R. doi:10.1016/S0009-2614(01)01345-8.
^Miessler, G. L. (1999). Inorganic Chemistry. Prentice Hall.
core electrons of an atom form the atomic core. Coreelectrons are tightly bound to the nucleus. Therefore, unlike valence electrons, coreelectrons play...
valence electrons and form a negative ion, or else to share valence electrons and form a covalent bond. Similar to a coreelectron, a valence electron has...
accompanied by the emission of an electron from the same atom. When a coreelectron is removed, leaving a vacancy, an electron from a higher energy level may...
has 2 electrons, and so on. The configuration is often abbreviated by writing only the valence electrons explicitly, while the coreelectrons are replaced...
a core state electron can be removed leaving behind a hole. As this is an unstable state, the core hole can be filled by an outer shell electron, whereby...
periods and electron wavefunctions that approximate, under some conditions, classical orbits of electrons about the nuclei. The coreelectrons shield the...
mites). When a stellar core collapses, the pressure causes electrons and protons to fuse by electron capture. Without electrons, which keep nuclei apart...
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure)...
describing the location and wave-like behavior of an electron in an atom. This function describes the electron's charge distribution around the atom's nucleus...
systems with negative electron affinity and the emission from excited states, or a few hundred keV photons for coreelectrons in elements with a high...
related to Electron shell diagrams. Periodic table (electron configurations) Electron counting 18-electron rule Core charge Re: Why do electron shells have...
The electron ( e− , or β− in nuclear reactions) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first...
called an electron capture supernova. ... In an electron capture supernova, as the core runs out of fuel, gravity forces electrons in the core into their...
Electron energy loss spectroscopy (EELS) is a form of electron microscopy in which a material is exposed to a beam of electrons with a known, narrow range...
anomalous Zeeman effect. In December 1924, Wolfgang Pauli showed that the coreelectron angular momentum was not related to the effect as had previously been...
many-electron Schrödinger equation can be very much simplified if electrons are divided in two groups: valence electrons and inner coreelectrons. The...
nearly free electron model (or NFE model and quasi-free electron model) is a quantum mechanical model of physical properties of electrons that can move...
energy order for the 55th electron outside the xenon core proceeds as follows in the isoelectronic series of caesium (55 electrons): Cs0: 6s < 6p < 5d < 7s...
collecting the emitted secondary electrons generated in the electron cascade that follows the creation of the primary core hole in the absorption process...
modern 18-column periodic table, the d electrons of zinc, cadmium, and (almost always) mercury behave as coreelectrons and do not take part in bonding. This...
to replace the atomic all-electron potential (full-potential) such that core states are eliminated and the valence electrons are described by pseudo-wavefunctions...
electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons....
sign due to all the coreelectrons of the atoms. Stronger forms of magnetism usually require localized rather than itinerant electrons. However, in some...
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