우주와생명제 9 강 보어모델
INTRODUCTION 수소의보어모델 : 원자구조의한패러다임 The Bohr Model of Hydrogen: A Paradigm for the Structure of Atoms 리그덴의저서 수소 에서발췌 Excerpts from Hydrogen by Rigden 닐스보어 Niels Bohr (1885-1962)
9-1 톰슨의전자 (Thomson s Electron) 닐스보어가 1911 년에박사학위를받았을때물리학의세계는 가능성을잉태하고있었다. When Niels Bohr received his doctorate in 1911, the world of physics was pregnant with potential.
9-1 톰슨의전자 (Thomson s Electron) 보어등이활약할장을마련한발견을이룬사람중하나는 1884 년에 28 세의나이로맥스웰, 레일리경에이어케임브리지대학교의실험물리학 캐번디시교수가된 J.J 톰슨이었다. One of those whose discoveries prepared the field for Bohr and others was J.J. Thomson (1856-1940), who in 1884, at the age of twenty-eight, became Cavendish Professor of Experimental Physics at the University of Cambridge, following in the steps of James Clerk Maxwell (1831-1879) and Lord Rayleigh (1842-1919). https://upload.wikime dia.org/wikipedia/com mons/5/57/james_cle rk_maxwell.png https://upload.wiki media.org/wikipedi a/commons/5/54/st rutt.jpg https://upload.wi kimedia.org/wikip edia/commons/th umb/c/c1/j.j_tho mson.jpg/205px- J.J_Thomson.jpg
9-1 톰슨의전자 (Thomson s Electron) 톰슨이음전하를띠는전자를발견하면서원자가어떤공통적인입자로이루어졌다는프라우트의생각이새롭게중요성을가지게되었다. https://upload.wikimedia.org/wikipedia/co mmons/thumb/5/52/prout_william_painti ng.jpg/220px-prout_william_painting.jpg 프라우트 William Prout 1785-1850 With Thomson s discovery of the negatively charged electron, Prout s idea that atoms were built up from some common entity took on a new significance.
9-1 톰슨의전자 (Thomson s Electron) 프라우트에게이공통적인입자는수소였지만, 1897 년직후에는이것은전자가되었다. For Prout, the common entity was hydrogen; in the years immediately following 1897, the common entity became the electron.
9-1 톰슨의전자 (Thomson s Electron) 1903년에톰슨은수소에는약천개의전자가들어있을것이라고주장했다. 1906년에톰슨은원자모델에관해서가장중요한기여를했다. In 1903 J.J. Thomson asserted that hydrogen contains about a thousand electrons. In 1906, Thomson made perhaps his greatest contribution to the pursuit of an atomic model.
9-1 톰슨의전자 (Thomson s Electron) 몇가지의논리를동원해서톰슨은원자에들어있는전자의수는대략적으로원자량과같다고결론내렸다. 그렇다면수소원자에는전자가한개밖에없을것이다. H With several lines of reasoning, Thomson concluded that the number of electrons in an atom was approximately equal to an atom s atomic weight. On this basis, there would be only one electron in a hydrogen atom.
9-2 러더포드의원자핵 (Rutherford s Nucleus) 러더포드는알파입자를좋아했다. 1898년에그것을발견한것은그였으니까말이다. 1908년에그는알파입자가 +2의전하를가지는것을밝혔다. https://upload.wi kimedia.org/wiki pedia/commons/ d/de/ernest_ruth erford_1908.jpg https://upload.wikime dia.org/wikipedia/com mons/thumb/7/79/alp ha_decay.svg/1280px- Alpha_Decay.svg.png Rutherford liked alpha particles. After all, he had discovered them in 1898. In 1908 he established that the alpha particle carried a double positive charge.
9-2 러더포드의원자핵 (Rutherford s Nucleus) 러더포드와그의조수였던한스가이거는알파입자의가는빔을알루미늄이나금박을향해쏘았다. Rutherford and his assistant Hans Geiger directed a well-defined beam of alpha particles at thin foils of aluminum and gold.
9-2 러더포드의원자핵 (Rutherford s Nucleus) 알파입자는대부분얇은막을그대로통과했지만, 일부는특히 금박의경우에는작은각도로휘어졌다. Most of the alpha particles passed straight through the foil, but some of them were scattered through a small angle, especially from the foils composed of gold atoms.
9-2 러더포드의원자핵 (Rutherford s Nucleus) 러더포드는가이거를도와주던학부생인마스덴에게제안을했다. 러더포드의제안은 큰각도로휘어지는알파입자는없는지조사해보지그래 식이었다. http://www.chemistryexplained.com/images/chfa_04_ img0818.jpg Rutherford made a suggestion to Ernest Marsden, an undergraduate who was helping Geiger. Rutherford s suggestion went something like this: Why don t you see if some alpha particles are scattered at large angles?
9-2 러더포드의원자핵 (Rutherford s Nucleus) 1911 년 3 월에이 새로운원자모델이 과학계에발표되었다. In March 1911, this new model of the atom was conveyed to the community of science. 그후 1912 년 10 월에 러더포드는처음으로 핵이라는말을사용했다. Later, in October 1912, Rutherford used the term nucleus for the first time.
9-3 보어의원자 (Bohr s Atom) 어느누구보다도, 어느다른 물리학자보다도보어는양자혁명을 이끈정신이었다. More than any other person, more than any other physicist, Bohr was the guiding spirit of the quantum revolution. http://www.umuseke.r w/wp-content/uploads /2015/04/EMC2- Facebook-Cover.jpg 아인슈타인 1921 년노벨물리학상 보어 1922 년노벨물리학상 http://98a4980578083 abe0fc6-26cdb33025b4deaf9c0 a6e9a3953d227.r43.cf 2.rackcdn.com/26C342 D0-389E-45CF-B45A- FF88C2995CDD.jpg
9-3 보어의원자 (Bohr s Atom) 대부분물리학자들은 20 세기물리학에서보어보다더크게 기여한사람은아인슈타인밖에없다고인정한다. Bohr s contribution to twentieth-century physics is acknowledged by most physicists as second only to Albert Einstein s.
9-3 보어의원자 (Bohr s Atom) 러더포드를따라서보어는수소원자를양전하를가진아주작은핵과닫힌궤도들을따라그주위를도는한개의전자로묘사했다. Following Rutherford, Bohr depicted the hydrogen atom to be a positively charged nucleus of very small dimensions and an electron describing closed orbits around it.
9-3 보어의원자 (Bohr s Atom) 보어는 안정한궤도들 이라는표현을썼는데, 그는이궤도에서는에너지복사가없다고주장해서 19 세기 전자기학에서확립된핵심원리를위반했다. Bohr used the term stationary orbits in which, he asserted, there is no energy radiation, thereby violating the established tenets of nineteenth-century electromagnetism.
9-3 보어의원자 (Bohr s Atom) 보어는에너지에양자조건을부여해서어떤특정한에너지들만이허용된다고주장했다. Electron Bohr placed a quantum condition on the energy; namely, he asserted that only certain energies are permitted. 수소원자의에너지가크면궤도도크다. Proton 1 2 3 The larger the energy state of the hydrogen atom, the bigger the orbit.
9-3 보어의원자 (Bohr s Atom) 그의모델로부터보어는여러궤도의반지름을계산할수있었고, 가장작은 궤도의반지름으로부터수소원자의지름, 그러니까크기를계산할수있었다. 보어가그의모델로부터계산한수소원자의크기는 1.1 옹스트롬이었다. From his model, Bohr was able to calculate the radii of the various orbits and thus, from the radius of the smallest orbit, he could calculate the diameter of the hydrogen atom and hence, its size. The dimension of the hydrogen atom, as Bohr calculated from his model, was 1.1 A (1.1 x 10-8 cm). 측정값약 1 옹스트롬
9-4 수소의선스펙트럼 (Hydrogen Line Spectrum) 보어는또하나의기본적아이디어를수소원자에도입했는데이놀라운아이디어를사용해서그는원자의스펙트럼을설명하는메커니즘을제안했다. Bohr brought one more basic idea to his treatment of the hydrogen atom, an amazing and a portentous idea: he proposed a mechanism to account for the spectrum of an atom.
9-4 수소의선스펙트럼 (Hydrogen Line Spectrum) 1885 년 발머 (Balmer) https://upl oad.wikim edia.org/ wikipedia/ commons/ 5/51/Balm er.jpeg 빨강색선 : ν 3 = 3.290 10 15 (1/2 2 1/3 2 ) s -1 연두색선 : ν 4 = 3.290 10 15 (1/2 2 1/4 2 ) s -1 하늘색선 : ν 5 = 3.290 10 15 (1/2 2 1/5 2 ) s -1 파랑색선 : ν 6 = 3.290 10 15 (1/2 2 1/6 2 ) s -1
9-4 수소의선스펙트럼 (Hydrogen Line Spectrum) 막스플랑크의 1900년연구에발맞추어보어는수소원자에서허용되는두상태의에너지차이를플랑크상수와빛의진동수로나타냈다. n = 3 n = 2 n = 1 +Ze E = hf E 3 E 2 = hf In keeping with the 1900 work of Max Planck, Bohr expressed the energy difference between tw of his allowed states in the hydrogen atom in terms of Planck s constant and the frequency of light.
9-4 수소의선스펙트럼 (Hydrogen Line Spectrum) 보어는수소원자에서허용된상태의특정한 에너지를표현하는명확한식을썼다. 이식에서 m 은전자의질량, e 는전자의전하, h 는 플랑크상수, 그리고 n 는정수이다. Bohr wrote an explicit expression for the specific energies of the allowed states of the hydrogen atom. where m = mass of the electron, e = the electric charge of the electron, h = Planck s constant, and n = an integer. E n = 2π 2 me 4 /n 2 h 2 http://www.f reewebs.com /kienitz/imag es/planck.jpg 플랑크 Max Planck 1918 년노벨물리학상
9-4 수소의선스펙트럼 (Hydrogen Line Spectrum) 이과정에서어느시점에보어가발머의식을알게 되었고, 그때 순간적으로명확 해졌다. 발머의식과그의 ( 에너지 ) 표현에서모두분모에 n 2 이들어있는것이보어에게단서가되었을것이다. At some point during this process, Balmer s formula came to Bohr s attention, and it became immediately clear. The clue for Bohr may well have been the appearance of n 2 in the denominators of both Balmer s formula and his expression.
9-5 양자혁명 (Quantum Revolution) 보어모델이후에그의명성은엄청나게높아졌는데그것은그의논문때문이라기보다는그가다른사람들에게미친영향때문이었다. After Bohr s model, his reputation grew to enormous proportions not so much as the consequence of the papers he wrote, but as a consequence of the influence he exerted on others. https://upl oad.wikim edia.org/ wikipedia/ commons/ f/f4/heise nberg,we rner_1926.jpeg https://u pload.wi kimedia. org/wiki pedia/co mmons/ 4/43/Pa uli.jpg https://upl oad.wikim edia.org/ wikipedia/ commons/ thumb/c/c f/dirac_4.j pg/162px- Dirac_4.jp g
9-5 양자혁명 (Quantum Revolution) 1925-26 년사이에원자세계를새롭게이해하는 물리학인양자역학이태어났다. 빅터와이스코프의말에따르면물리학의그위대한 시기에 보어와그의제자들은우주의정신에접속했다. In 1925-26, quantum mechanics, a new physics that brought understanding to the world of the atom, was created. In that great period of physics, wrote Victor Weisskopf, Bohr and his men touched the nerve of the universe. http://blog.li b.umn.edu/it comm/learni ngabroad/ass ets_c/2013/0 5/IMG_3469[ 1]-thumb- 480x360-155493.jpg https://uploa d.wikimedia. org/wikipedia /commons/1/ 1a/Heisenber gbohr.jpg
9-5 양자혁명 (Quantum Revolution) nuclear model ~ 400 BC 1808 1897 1911 line spectrum 1859 quantum theory 1885 1888 1900 1905 Bohr model 1913 wave mechanics 1924 1926 1927 atomic physics quantum chemistry 1939 chemical bonding octet rule 1811 1869 1894 1916
Review Helium is doing well With two electrons in the first shell. After fluorine comes neon And after chlorine comes argon With eight electrons in the second shell. The rule is called octet Though for helium it is duet.