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3- The atom changes from a stationary state to another stationary state only by absorbing or emitting photon (energy).
Typology: Schemes and Mind Maps
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Bohr’s model of the atom Based on: Rutherford: nuclear model of the atom ( p +^ : center, e -^ : orbit) Balmer-Rydberg’s positive integer quantum numbers Planck’s and Einstein’s quantized energy concept (and photon) 1- Classical physics does not apply to particles of atomic or sub-atomic dimensions. 2- The energy of an electron in a hydrogen atom is quantized (allowable energy level). 3- The atom changes from a stationary state to another stationary state only by absorbing or emitting photon (energy). 4- An hydrogen atom radiates energy only when the electron jump from one allowed stationary state to a lower energy stationary state.
Bohr’s equation for the energy of an atom (valid for a single electron atom)
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2 B = Bohr’s energy (2.178x10-^18 J) Z = charge of the nucleus (H = +1, Li = +3) n = main quantum number; associated to the level of the electron orbit. small value of n = electron closer to the nucleus lower energy level. Ground state: Lowest allowed energy level Excited state: any other energy level Ionized: the electron is removed from the atom, n = ∞. When the electron is completely removed from the nucleus, E(atom) = 0. ∆E(atom) = E(atom final state) – E(atom initial state) ∆E(atom) > 0: energy absorbed, n value rises (higher electron orbit) ∆E(atom) < 0: energy released, n value decreases Note ∆E(atom) is ALWAYS followed by the emission/absorption of a photon of equal energy. The energy of a photon is always positive. │∆E(atom)│ = E(photon) = h n