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Semiconductor Devices
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
Stability of an atom is an important concept in the status of semiconductor materials. Atoms cannot possess more than 8 electrons in the valence band. When exactly 8 electrons appear in the valence band, an atom is considered to be stable. The valence electrons in a stable atom become tightly bound together. Atoms of this type are excellent insulators. They do not have any free electrons for electric conduction. Gases such as neon, argon, krypton, and xenon are examples of stabilized elements. They will not mix with other materials because of this condition. A stabilized gas is generally called inert.
Background theory
Published in Michael de Podesta, Understanding the Properties of Matter, 2020
At separations greater than a few atomic diameters, atoms barely interact with one another. The interactions between atoms occur when they are brought close together and are caused only by the electrical interactions between the atoms. This single fact is worth repeating: the interactions between atoms are caused only by electrical interactions. The magnitude of the interaction is dominated by the outer part of the electronic structure around the atom. The electrons in the outer part of the structure are called valence electrons. The number and distribution of the valence electrons strongly affects the physical and chemical properties of atoms, and of the substances of which the atoms are a part.
Structure of Molecules
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Valence is a whole number that represents the ability of an atom or a group of atoms to combine with other atoms or groups of atoms. The valence is determined by the number of electrons that an atom can lose, add, or share. Therefore, valence is the number of electrons available for chemical bond formation for each atom. Valence also relates to the number of bonds an atom can form and remain neutral. Valence is 8-#, where # is the last digit of the group number for an atom: # is 4 for Group 14, 5 for Group 15, 6 for Group 16, and 7 for Group 17. What is the valence of each of the following: C, H, N, O, F?
Redox potential as an important characteristic of the chemical and biological state of surface waters (review)
Published in Chemistry and Ecology, 2023
Peter Linnik, Volodymyr Osadchyi, Natalia Osadcha, Rostyslav Linnik
Much attention has been paid to the study of the redox potential in surface and groundwater, but much data obtained are siloed and scattered in different sources. Therefore, this paper reviews existing literature on Eh-potential, integrates a knowledge on the most important potential- regulating systems in surface waters, and analysing their influence on the polyvalent element species affecting the ecological status of water bodies. Polyvalent elements demonstrate their ability to exist in multiple oxidation or valence states depend on the chemical environment and reactions they are involved in. The most important polyvalent elements include nonmetals (S, N, Se); transition metals (Fe, Cu, Cr, Mn, V, Mo) and semimetals (As).