BIOS 208 1st EditionExam 1 Study GuideI. IsotopesII. Atomic Number and Atomic MassIII. Isotopes of CarbonIV. Hydrogen IsotopesV. Unstable Radioactive IsotopesI. Biological Uses of IsotopesII. Isotope radiometric datingIII. Shroud of TurinIV. Chemical Bonds and Electron OrbitalsV. Electron ShellsVI. Periodic TableI. Biological Uses of IsotopesA. Carbon dating. From the decay of unstable 14C, it can be determined when a living organism died, as 14C decreases.B. Radiotracers can be used in metabolic research or in medicine. e.g. 32P in DNA in nucleusof cells.II. Isotope radiometric datingA. As radioisotopes decay less of the parent isotope remains.B. After one half life, half the isotope remains e.g. t1/2 of 32P =14 days.C. If you start with 100 g, how much will be present after 28 days? 2 half-lives…so 25g as ¼ remains 56 days.III. Shroud of TurinA. Shroud of Turin is a specimen of religious significance and a subject of much study and speculation.B. Was thought to be cloth material in which the body of Christ was shrouded for burial.C. Laboratories at the universities of Oxford and Arizona radiocarbon dated samples of the shroud and concurred that the samples they tested were less than 1000 years old and dated from the Middle Ages between 1260 and 1390.D. Since 2005, at least four articles have been published stating that the samples used for the dating test may not have been representative of the whole Shroud.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.E. "It's fair to say that, despite the seemingly definitive tests in 1988, the status of the Shroud of Turin is murkier than ever. The nature of the image and how it was fixed on the cloth remain deeply puzzling".F. PET scan using radioactive glucose labeled with 14C to detect metabolic activity, associated with throat cancer.IV. Chemical Bonds and Electron OrbitalsA. Electron orbitals are usually drawn as spheres showing the statistical probability of the location of the electron (e-).B. Electron orbitals contain one or two electrons (max).C. Orbitals closest to the nucleus of the atom have the lowest energy and are filled first.V. Electron ShellsA. Energy (E) is the ability to do work.B. Energy is needed (absorbed) when e- go to a higher level and energy is lost/released when e- go to a lower level.C. Lowest levels filled first as they are most stable.D. Electron orbital shapes are related to probability of where electrons reside.E. Electrons with the same energy are in the same shell and shells can contain several “orbitals”.F. 1s first shell has 1 orbital 1 or 2 e-.G. 2s, 2p x3 second shell has 4 orbitals 1 to 8 e-.H. e.g. 10 Ne has atomic no. of 10.a) 1s, 2s, 2p x3.b) 2 2 6 = total of 10 electrons.VI. Periodic TableA. Elements in the same row have the same outer shell or valence shell and elements in the same column have the same number of e- in their valence shell (valence e-).B. These elements have similar chemical properties. E.g. Li and Na are both reactive metals,Ne and Ar are both inert gases.C. Atoms with the same no. of e in outermost shell show similar (periodic) properties e.g. both Cl and F have 7 “valence” e- and they are very reactive gases.D. Elements in the same row have the same outermost shell.E. Elements in the same column have the some no. of e in outermost shell.F. Most elements with unfilled valence shells are unstable.G. Atomic Stability can be achieved by:a) Filled valence shell or Electro-neutrality.b) No. of e- = no. of P so net charge = 0.c) e- are paired (orbits are filled).H. Noble gasses are the only elements that satisfy the 3 stability rules.I. All other elements are inherently unstable.J. They can become stable by interacting with each other via bonding.a) For example, two hydrogen atoms:b) H - H & H:H
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