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Second rule: the electrostatic valence rule. For a given cation, Pauling defined [2] the electrostatic bond strength to each coordinated anion as , where z is the cation charge and ν is the cation coordination number. A stable ionic structure is arranged to preserve local electroneutrality, so that the sum of the strengths of the electrostatic ...
Le Chatelier's principle (pronounced UK: / lə ʃæˈtɛljeɪ / or US: / ˈʃɑːtəljeɪ / ), also called Chatelier's principle (or the Equilibrium Law ), [ 1][ 2] is a principle of chemistry used to predict the effect of a change in conditions on chemical equilibrium. [ 3] The principle is named after French chemist Henry Louis Le Chatelier ...
There are two possible structures for hydrogen cyanide, HCN and CNH, differing only as to the position of the hydrogen atom. The structure with hydrogen attached to nitrogen, CNH, leads to formal charges of -1 on carbon and +1 on nitrogen, which would be partially compensated for by the electronegativity of nitrogen and Pauling calculated the net charges on H, N and C as -0.79, +0.75 and +0.04 ...
e. In physics and chemistry, the law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so the quantity can neither be added nor be removed. Therefore, the quantity of mass is ...
Hund's rules. In atomic physics and quantum chemistry, Hund's rules refers to a set of rules that German physicist Friedrich Hund formulated around 1925, which are used to determine the term symbol that corresponds to the ground state of a multi-electron atom. The first rule is especially important in chemistry, where it is often referred to ...
v. t. e. In quantum mechanics, the Pauli exclusion principle states that two or more identical particles with half-integer spins (i.e. fermions) cannot simultaneously occupy the same quantum state within a system that obeys the laws of quantum mechanics. This principle was formulated by Austrian physicist Wolfgang Pauli in 1925 for electrons ...
t. e. The second law of thermodynamics is a physical law based on universal empirical observation concerning heat and energy interconversions. A simple statement of the law is that heat always flows spontaneously from hotter to colder regions of matter (or 'downhill' in terms of the temperature gradient).
Valence shell electron pair repulsion ( VSEPR) theory ( / ˈvɛspər, vəˈsɛpər / VESP-ər, [ 1]: 410 və-SEP-ər[ 2]) is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. [ 3] It is also named the Gillespie-Nyholm theory after its two main developers ...