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Chemistry Returning to discuss the atomic model proposed by Rutherford, which established that atoms were composed of a dense, positively charged nucleus surrounded by negatively charged electrons, we point out that this model had a major problem identified by some scientists of the time. The problem of a model of the planetary type (electrons orbiting the nucleus like planets orbiting the sun) is that it does not take into account the energy loss of electrons in this situation. An electrically charged particle accelerated and emits electromagnetic radiation and therefore loses energy in the process. As a result the electrons could not maintain a "stable orbit" and should gradually approach the core, in a "spiral orbit" until, in the end, they collide with it. As the "atomic collapse" described above does not occur in the real world, Henry David Niels Bohr, in 1913, proposed a new model whereby, in addition to solving this basic difficulty of the Rutherford model, allowed to explain theoretically the electromagnetic spectrum emitted by the element chemical hydrogen experimentally determined. A theoretical model allows us to explain, or provide for an experimental observation consistently, is of great value, and in view of this, the proposed Bohr had a great impact at the time. The Bohr model consists of the following basic ideas, which are based on ideas already worked by Planck and Einstein in other contexts: Electrons around the atomic nucleus are located in quantized energy levels; Laws of classical mechanics (Newton's laws) are not valid for the passage of an electron from one level to another; Occurs when the passage (or jump) of an electron between different levels of energy, the electron must absorb or emit energy (the electron absorbs energy if he passes a lower level to a higher energy and emits energy in otherwise) as a photon must have energy exactly equal to the energy difference between the respective levels. Allowed energy levels depend on integer values for the named principal quantum number n (n = 1, 2, 3, 4 ...). According to the equation L = n. ) Wherein L is called an orbital angular momentum, n is the principal quantum number, h is Planck's constant and is the number pi. The Bohr model explains in a reasonable system containing an electron (the hydrogen atom), but can not explain atoms with more than one electron.
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Kemija Vrativši se raspravljati o atomsku model koji predlaže Rutherford, kojom je utvrđeno da su atomi sastavljeni od guste, pozitivno nabijene jezgre okružen negativno nabijenih elektrona, možemo istaknuti da je ovaj model je imao veliki problem koji je identificiran od strane nekih znanstvenika toga doba. Problem model planetarnog tipa (elektroni orbitiraju oko jezgre poput planeta koji kruže oko sunca) je da se ne uzima u obzir gubitak energije elektrona u ovoj situaciji. Električki nabijena čestica ubrzala i emitira elektromagnetsko zračenje i stoga gubi energiju u procesu. Kao rezultat se elektroni ne mogu održavati "stabilnu orbitu", a treba pristupiti postupno jezgru, u "spiralnoj putanji" dok se, na kraju, one se sudaraju s njom. Kao "atomska kolaps" gore opisano ne dogodi u stvarnom svijetu, Henry David Niels Bohr, 1913, predložio novi model kojim se, osim rješavanja ovog osnovno teškoće Rutherford modelu, dozvoljeno objasniti teoretski elektromagnetskog spektra emitiran elementa kemijskih vodika eksperimentalno određuje. Teoretski model omogućuje nam objasniti, ili osigurati eksperimentalnog promatranja dosljedno, od velike je vrijednosti, as obzirom na to, predloženi Bohr je imao veliki utjecaj na vrijeme. Bohr model sastoji se od sljedećih osnovnih ideja, koja se temelji na idejama već odradili Planck i Einstein u drugim kontekstima: Elektroni oko atomske jezgre nalaze se u kvantiziranim razine energije; Zakoni klasične mehanike (Newtonovi zakoni) ne vrijede za prolaz elektrona iz jedne razine u drugu; Javlja se kada je prolaz (ili skok) od elektrona između različitih razina energije, elektron mora apsorbirati ili emitirati energiju (elektronska upija energiju ako on prolazi niže razine na višu razinu energije i emitira energiju u inače) kao foton mora imati energiju točno jednaku energetsku razlike između pojedinih razina. Dopuštenih razina energije ovisi o integer vrijednosti za navedene glavni kvantni broj n (n = 1, 2, 3, 4 ...). Prema jednadžbi L = n. ) Pri čemu je L se zove orbitalna kutnog momenta, n je glavni kvantni broj, h je Planckova konstanta, a je broj pi. Bohr model objašnjava u razumnom sustavu koja sadrži jedan elektron (atom vodika), ali ne mogu objasniti atome s više od jednog elektrona.