Atoms tiny wonders worth studying

1. Atoms tiny wonders worth studying Energy states of electrons in atoms are represented by this formula. Understand all the symbols and implications of this formula. Atoms

2. The Hydrogen Spectrum Balmer’s findingBalmer series, ni = 2; snd nf = 3, 4, 5, ... Rydberg’s formula Rydberg constant Wave number = – R (–– – ––) 1 1nf2ni2 Atoms

3. Energy States of e- in H Atoms

4. The Discovery of X-rays Rontgen’s letter publish in Nature (Jan 23, 1896) with a photo showing a hand skeleton of his wife proclaimed the discovery of X-rays. (imagine.gsfc.nasa.gov/docs/science/know_l1/history1_xray.html) Image of rabbit earspring8.or.jp/ENGLISH/general_info/overview/imaging.html X-ray image of Mrs. Rontgen’s hand Atoms Tell the story of X-ray discovery.

5. Generation of X-rays What is the principle of X-ray generation? Atoms

6. Characteristic X-rays and energy levels of electrons in elements What are characteristic X-rays and why they are generated? Atoms

7. Moseley’s Law = h  = E What is Moseley’s law and how it impacts science? Atoms

8. X-ray Diffraction Explained Typical diffraction diagram of a quasicrystal, exhibiting 5-fold or 10-fold rotational symmetry Atoms

9. Crystal Structures Revealed by X-ray Diffractions X-ray diffraction revealed structures of many substances and impacted science and engineering development. Two are shown. Atoms

10. Discovery of Radioactivity Methodology in Becquerel’s discovery of radioactivity is intriguing and interesting. How do you explain the discovered phenomenon? What & why? Atoms

11. Properties of Radioactive Rays What is radioactivity? Atoms

12. Rutherford -particle Scattering Experiment What is the alpha scattering experiment? What did he observed, and how he explained it? Atoms

13. The Rutherford Atoms Rutherford’s Conclusion Radius of atoms: 1e-10 m H 37 He 50 Li 150 F 71 Fr 170 Radius of nuclei: 1e-15 m rnuc= 1.2 A1/3 fm(1E-15) Atoms

14. The Bohr Atoma tiny solar system Bohr applied the Idea of Max Planck, and used results from Rutherford. He made an assumprion: m v r = h/2His results are given next What is the Bohr atom?How did he arrive such a model? If U care Atoms

15. Energy States of Electrons in the Bohr Atom Results of Bohr atom m v r = h/2 En = Atoms

16. A Quantum Mechanical View of Energy States In a large system, the energy states form a band. As the system gets smaller, energy states progressively became discrete. Quantum mechanics is required to deal with microscopic systems and discrete energy states. Atoms

17. The Development of Quantum Mechanics Max Planck’s photon: E = h nRutherford atomThe Bohr atom (solar system) Heisenberg’s uncertainty principleLouis de Broglie (mater wave): = h / m vSchrodinger: Treat particles as waves What are the philosophies behind quantum? Atoms

18. Quantum Mechanical View of Energy States of Electrons in the Atoms Diagram energy states in atoms and explain the periodic table. Atomic Orbitals 4f– – – – – – – 4d– – – – – 4p– – – 4s– 3d– – – – – 3p– – – 3s– 2s– 2p– – – 1s– Atoms

19. Quantum Mechanics Led to and the Periodic Table of Elements Filling electrons in energy states gives the electronic configurations of all elements. Electronic configurations of some light elements Ne 1s2 2s22p6 F 1s2 2s22p5 O 1s2 2s22p4 N 1s2 2s22p3 C 1s2 2s22p2 B 1s2 2s22p1 Be 1s2 2s2 Li 1s2 2s1 He 1s2 H 1s1 Atomic Orbitals 4f– – – – – – – 4d– – – – – 4p– – – 4s– 3d– – – – – 3p– – – 3s– 2s– 2p– – – 1s– Atoms

20. The time line of our understanding of the atomic nuclei Yin Yang and Primal Substance 1704 I. Newton – Solid body 1803 J. Dalton – atomic theory 1832 M. Faraday – electrolysis 1879 W. Crookes – discovered electrons 1886 W. Rontgen – X-rays H. Becquerel – radioactivity Goldstein – kanal rays 1897 J.J. Thomson – e/m ratio - Canal rays (H atom) 1898 E. Rutherford – studied radioactivity 1900 Soddy – transmutation of elements 1911 E. Rutherford – dense +ve nuclei 1914 H.G.J. Moseley – Moseley law 1922 N. Bohr – Bohr atom model 1923 de Broglie – particles as waves 1927 Heisenberg – uncertainty principle 1927 Cockcroft /Walton – split the atom Some facts about atoms: Radii of atoms ~ 1e-10 m (Å) most space occupied by electrons Radii of atomic nuclei ~ 1e-15 m (fm) most mass concentrated in nuclei Atoms

21. Properties of Protons 1886 Goldstein discovered canal rays 1898 Wien and Thomson identified them as nuclei of H and determined some properties of protons The atomic number used in Moseley’s law turns out to be the number of protons in the nuclei Protons were thought to be fundamental particles Rest1.6726231x10–27 kg mass1.00727647 amu 938.2723 MeV Spin½ Magnetic 2.7928474 Nmoment Electric+1 atomic chargecharge What is a proton? Atoms

22. Discovery of Neutrons It has been shown by Bothe and others that beryllium when bombarded by -particles of polonium emits a radiation of great penetrating power, .… Be +  = C + n + Energy B + n = Li +  It is to be expected that many of the effects of a neutron in passing through matter should resemble those of a quantum of high-energy, and it is not easy to reach the final decision between the two hypotheses. Up to the present, all the evidence is in favour of the neutron, while the quantum hypothesis can only be upheld if the conservation of energy and momentum be relinquished at some point. James Chadwick, Feb. 23, 1932 How was neutron discovered, and what is it? Atoms

23. Neutron Scattering Techniques THE ROYAL SWEDISH ACADEMY OF SCIENCES 12 October 1994 The Royal Swedish Academy of Sciences has decided to award the 1994 Nobel Prize in Physics for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter with one half to Professor Bertram N. Brockhouse, McMaster University, Hamilton, Ontario, Canada, for the development of neutron spectroscopy and one half to Professor Clifford G. Shull, MIT, Cambridge, Massachusetts Atoms

24. Applications of neutrons from a research reactor for studying structures and dynamics Atoms

25. Isotope Discovery of neutron in atomic nuclei led to the concept of isotopes. Atomic weight Na 23Mg 24.3Cl 35.5Ar 40.K 39Ca 40Cu 63.5 Why atomic weights are not all integers? Can atoms of an element have different number of neutrons? What are isotopes? What are isotopes? What are stable isotopes of C, Cl, Ca? Atoms

26. Deuterium and Isotopes of Hydrogen Does hydrogen have isotopes? How to separate isotopes? How are their properties different? H2 HD D2 Triple point /K 13.96 16.60 18.73 Vapor pressure 128.6 92.8 54.0 at TP Heat of vapori- 117 159 197 zation at TP Boiling point (K) 20.39 22.13 23.67 Heat of vapori- 903 1074 1225zation at BP Harold C. Urey (1893-1981)1934 Nobel Laureate in Chemistry for his discovery of heavy hydrogen. Atoms

27. Urey Experiment About Life The early Earth atmosphere of NH3, CH4, H2O, under discharge produced organic matter including aminoacids that are essential compounds for life form. Atoms

28. Atomic Mass, Abundance and Atomic Weight Isotope atomicmass Abundance atomicmass*abundance 1H 1.00782503 0.99985 1.007674 2H 2.014102 0.000148 0.000298 3H 3.016049 Trace ---- +________ Atomic weight for H = 1.007674 + 0.00298 = 1.007972 Practice the evaluation of atomic weight of an element using the same method as this example shows. Atoms

29. Notations for Nuclides Representations of a nuclide MEZ zEM MzE How isotope differ from nuclide? How are nuclides represented? 3T13He212C616O8235U92 238U92 234U92 239Pu94256Fm100 Atoms

30. The Quarks Based on the properties and relationships of particles known in 1962, Gell-Mann in the US and Y. Neémen of Israel predicted the existence and properties of some unknown particles in considerable detail. Gell-Mann and Zweig from Caltech suggested that some heavy particles such as protons and neutrons (called baryons) were made up from three entities called quarks, so named by Murray Gell-Mann after a quote "three quarks for muster Mark, sure he hasn't got much of a bark, etc..." from the novel Finnegan's Mark. J. Joyce, author of the novel, used quarks to rhyme with Mark, bark, lark etc.... Atoms

31. The Standard Model A Simplified Universe Generation First Second Third Quarksu, d c, s t, b Leptonse, nem,nm t, nt Scientific progress often involves establishing conventional wisdom. Other times, it is more a matter of defying it. Atoms

32. X-ray and Neutrons in the News • X-Ray Optical Systems, Inc., used the ATP funding to develop processes to fabricate and predict the performance of new “capillary optics” technology, which can bend and focus both X-rays and neutrons. Follow-on efforts to develop medical, industrial, and scientific applications are beginning to pay off for both the company and the nation. For example: • An instrument that generates beams with 100 times the intensity of other compact X-ray sources is an early spin-off of the project. • The new optics can identify and analyze the structure of proteins four to 10 times faster than conventional methods, a benefit in drug design. • Among industrial applications, the new optics offer a four- to 16-fold increase in X-ray intensity that is accelerating the development and monitoring of magnetic data-storage materials. • And this is only the beginning.“We have more active collaborations than we have employees, and we have identified more application areas than we have employees ... it’s an exciting time,” says David Gibson, the company president. Atoms