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The Avogadro constant, commonly denoted N A [1] or L, [2] is an SI defining constant with an exact value of 6.022 140 76 × 10 23 mol −1 (reciprocal moles). [3] [4] It is this defined number of constituent particles (usually molecules, atoms, ions, or ion pairs—in general, entities) per mole and used as a normalization factor in relating the amount of substance, n(X), in a sample of a ...
Mulliken charges arise from the Mulliken population analysis [1] [2] and provide a means of estimating partial atomic charges from calculations carried out by the methods of computational chemistry, particularly those based on the linear combination of atomic orbitals molecular orbital method, and are routinely used as variables in linear regression (QSAR [3]) procedures. [4]
For example, replacing m with q (total charge) and m 0 with q 0 (charge of each object) in the above equation will lead to a correct expression for charge. The number density of solute molecules in a solvent is sometimes called concentration, although usually concentration is expressed as a number of moles per unit volume (and thus called molar ...
Atomicity is the total number of atoms present in a molecule of an element. For example, each molecule of oxygen (O 2) is composed of two oxygen atoms. Therefore, the atomicity of oxygen is 2. [1] In older contexts, atomicity is sometimes equivalent to valency. Some authors also use the term to refer to the maximum number of valencies observed ...
Atomic units are chosen to reflect the properties of electrons in atoms, which is particularly clear in the classical Bohr model of the hydrogen atom for the bound electron in its ground state: Mass = 1 a.u. of mass; Charge = −1 a.u. of charge; Orbital radius = 1 a.u. of length; Orbital velocity = 1 a.u. of velocity [44]: 597
The mass number (symbol A, from the German word: Atomgewicht, "atomic weight"), [1] also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approximately equal to the atomic (also known as isotopic) mass of the atom expressed in atomic mass units.
The charge number equals the electric charge (q, in coulombs) divided by the elementary charge: z = q/e. Atomic numbers (Z) are a special case of charge numbers, referring to the charge number of an atomic nucleus, as opposed to the net charge of an atom or ion. The charge numbers for ions (and also subatomic particles) are written in ...
For example, if an ion carries one charge the m/z is numerically equivalent to the molecular or atomic mass of the ion in daltons (Da), where the numerical value of m/Q is abstruse. The m refers to the molecular or atomic mass number (number of nucleons) and z to the charge number of the ion; however, the quantity of m/z is dimensionless by ...