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The Bohr model of the hydrogen atom (Z = 1) or a hydrogen-like ion (Z > 1), where the negatively charged electron confined to an atomic shell encircles a small, positively charged atomic nucleus and where an electron jumps between orbits, is accompanied by an emitted or absorbed amount of electromagnetic energy (hν). [1]
The fine-structure constant gives the maximum positive charge of an atomic nucleus that will allow a stable electron-orbit around it within the Bohr model (element feynmanium). [20] For an electron orbiting an atomic nucleus with atomic number Z the relation is m v 2 / r = 1 / 4π ε 0 Z e 2 / r 2 .
Bohr calculated that a 1s orbital electron of a hydrogen atom orbiting at the Bohr radius of 0.0529 nm travels at nearly 1/137 the speed of light. [11] One can extend this to a larger element with an atomic number Z by using the expression for a 1s electron, where v is its radial velocity, i.e., its instantaneous speed tangent to the radius of ...
The Bohr radius ( ) is a physical constant, approximately equal to the most probable distance between the nucleus and the electron in a hydrogen atom in its ground state. It is named after Niels Bohr, due to its role in the Bohr model of an atom. Its value is 5.291 772 105 44 (82) × 10 −11 m. [1] [2]
In 1913, Niels Bohr proposed a model of the atom, giving the arrangement of electrons in their sequential orbits. At that time, Bohr allowed the capacity of the inner orbit of the atom to increase to eight electrons as the atoms got larger, and "in the scheme given below the number of electrons in this [outer] ring is arbitrary put equal to the normal valency of the corresponding element".
The Joint Institute for Nuclear Research in Dubna (a Russian city north of Moscow), proposed naming element 105 nielsbohrium (Ns) after Niels Bohr, while the University of California, Berkeley suggested the name hahnium (Ha) in honor of Otto Hahn. IUPAC recommended that element 105 be named dubnium, after Dubna.
His proposals were based on the then current Bohr model of the atom, in which the electron shells were orbits at a fixed distance from the nucleus. Bohr's original configurations would seem strange to a present-day chemist: sulfur was given as 2.4.4.6 instead of 1s 2 2s 2 2p 6 3s 2 3p 4 (2.8.6). Bohr used 4 and 6 following Alfred Werner's 1893 ...
Thus, hydrogen and the alkali metals are all 2 S 1 ⁄ 2, the alkaline earth metals are 1 S 0, the boron column elements are 2 P 1 ⁄ 2, the carbon column elements are 3 P 0, the pnictogens are 4 S 3 ⁄ 2, the chalcogens are 3 P 2, the halogens are 2 P 3 ⁄ 2, and the inert gases are 1 S 0, per the rule for full shells and subshells stated ...