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The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton (+1 e) or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 e. [2] [a]
Since metals can display multiple oxidation numbers, the exact definition of how many "valence electrons" an element should have in elemental form is somewhat arbitrary, but the following table lists the free electron densities given in Ashcroft and Mermin, which were calculated using the formula above based on reasonable assumptions about ...
(2/3 e)—Charge of up, charm and top quarks [2] 1.602 × 10 −19 C: The elementary charge e, i.e. the negative charge on a single electron or the positive charge on a single proton [3] 10 −18: atto-(aC) ~ 1.8755 × 10 −18 C: Planck charge [4] [5] 10 −17: 1.473 × 10 −17 C (92 e) – Positive charge on a uranium nucleus (derived: 92 x ...
The charge due to polarization is known as bound charge, while the charge on an object produced by electrons gained or lost from outside the object is called free charge. The motion of electrons in conductive metals in a specific direction is known as electric current .
In atomic physics, the effective nuclear charge of an electron in a multi-electron atom or ion is the number of elementary charges an electron experiences by the nucleus. It is denoted by Z eff . The term "effective" is used because the shielding effect of negatively charged electrons prevent higher energy electrons from experiencing the full ...
In that case, the charge of an ion could be written as =. The charge number in chemistry normally relates to an electric charge. This is a property of specific subatomic atoms. These elements define the electromagnetic contact between the two elements. A chemical charge can be found by using the periodic table.
The magnitude of the electrical charge of one mole of elementary charges (approximately 6.022 × 10 23, the Avogadro number) is known as a faraday unit of charge (closely related to the Faraday constant). One faraday equals 9.648 533 212... × 10 4 coulombs. [5]
e = elementary positive charge (i.e., magnitude of electron charge), m e = electron mass, k = Boltzmann constant = 1.38 × 10 −23 J/K, h = Planck constant = 6.62 × 10 −34 J⋅s, ϕ = work function of the cathode, ~ = mean electron reflection coefficient. The reflection coefficient can be as low as 0.105 but is usually near 0.5.