Chem 120A Fall Chem 120A

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1 Chem 120A Fall 2005 Tuesday & Thursday 8:00 9:20 AM Warren Lecture Hall Room 2005 Prof. Karsten Meyer Pacific Hall 4100E , Office Hours: Mo 10 12AM Handouts kmpages/courses.html Chem 120A Midterm I: 10/11 (30%) Midterm II: 11/08 (30%) Final Exam: Dec. 6, 8 11 AM (40%) 2 hr Review Session Sunday before Midterm Midterm I: 10/9 location & time tba Midterm II: 11/6 location & time tba 1

2 Chem 120A Fall 2005 PLEASE: Try to be on time I know you re busy, but please turn off your cell phones I know it s early, but please don t fall asleep (if you have to, don t sit in the first row) Chem 120A PLEASE: I know you re in a rush, but if you send me an , please address me and sign your If you do have a question please feel free to interrupt me any time!!! 2

3 Chem 120A In return, I PROMISE I promise I ll finish on time I promise I ll help you to understand I promise I ll follow the textbook & Solutions Manual strictly!!! Chem 120A 3

08 9/22 9/27 9/29 + 10/04 10/06 + 10/11 10/18 selected topics 10/20

4 Miessler & Tarr <Inorganic Chemistry> Brief Contents Midterm I Midterm II Oct. 11 Nov. 08 9/22 9/27 9/ /04 10/ /11 10/18 selected topics 10/20 10/ /27 11/ /03 11/10 11/15 11/17 11/22 11/24 Thanksgiving Final Exam Dec. 06, 8 11AM 11/ /01 Chem 120A 4

5 1. Contents 1-1 What is Inorganic Chemistry? Organic chemistry is defined as the chemistry of hydrocarbon compounds and their derivatives But how about CO, CO 2, and HCN for instance? Inorganic chemistry can be described broadly as the chemistry of everything else 5

6 1-1 What is Inorganic Chemistry? 1-1 What is Inorganic Chemistry? Organic chemistry is defined as the chemistry of hydrocarbon compounds and their derivatives Inorganic chemistry can be described broadly as the chemistry of everything else may be a little too broadly defined Organometallic chemistry bridges both areas; deals with metal-carbon bonds (incl. La & Ac) Bioinorganic chemistry bridges biochemistry & biology with inorganic chemistry (think hemes) Supramolecular~, Phyisical Inorganic ~ etc 6

7 1-2 Contrasts with Organic Chemistry? triple bond! Figure 1-1. Single- and Multiple Bonds in Organic and Inorganic Molecules 1-2 Contrasts with Organic Chemistry? Figure 1-2. Examples of Bonding Interactions 7

8 1-1 Contrasts with Organic Chemistry? Figure 1-3. Examples of Inorganic Compounds Containing H s & Alkyl Ligands 1-2 Contrasts with Organic Chemistry? Figure 1-4. Geometries of Inorganic Compounds 8

9 1-2 Contrasts with Organic Chemistry? Figure 1-5. Organometallic Compounds Containing π-bonded Aromatics 1-2 Contrasts with Organic Chemistry? Figure 1-6. Carbon-centered Metal Clusters 5- and 6-bonded C!? 9

10 1-2 Contrasts with Organic Chemistry? Figure 1-7. Fullerene Compounds C60 buckminsterfullerene* buckyballs but don t forget C70, C76, C84 *Richard Buckminster Fuller, creator of the geodesic dome 1-3 Big Bang Genesis of the Elements t = 0: The matter was not actually matter, but pure energy. It contained infinite mass, infinite density, and no volume: Singularity (like Black Holes) s: Mystery nobody knows, energy behaved as singularity s: Energy and matter are s: Temperature of K (the sun s surface T is 6000 K) symmetry breaking, forces begin to separate s: Inflation; universe grows exponentially (10 50 in s) 10

11 1-3 Big Bang Genesis of the Elements s: Inflation; universe grows exponentially (10 50 in s) As it cooled, the energy of the universe began to condense. It moved up the list from photons to quarks, neutrinos, electrons, and protons yippie yeah s: Era of Nucleosynthesis, almost all of the helium and deuterium nuclei, and some lithium 100 s: s all of the neutrons and protons had combined to form helium with trace amounts of a few other materials forming with it. 1-3 Big Bang Genesis of the Elements Then not much happened for about 300,000 years (75% H, 24% He) mass number 1 atomic number 1H proton + neutron 1 nuclear charge 1H 4 He 2 11

1 0 v e = a neutrino with no charge and a very small mass 1-3 Big Bang Genesis of the Elements most abundant

007 mass unit (amu) -1 0 e = e = electron of charge -1 and mass 1/1823 amu e = e + = positron of charge +1 and

12 1 0 v e = a neutrino with no charge and a very small mass 1-3 Big Bang Genesis of the Elements most abundant element in the universe heavy water cosmic radiation in high atmospheres 1 1H 2 3 1H 1 H Hydrogen H Deuterium D Tritium T % % % 1-3 Big Bang Genesis of the Elements Initial Event: 1 1H = p = proton of charge +1 and mass mass unit (amu) -1 0 e = e = electron of charge -1 and mass 1/1823 amu e = e + = positron of charge +1 and mass 1/1823 amu 1 0 v e = an antineutrino with no charge and a very small mass 1 0 n = a neutron with no charge and a mass γ = a gamma ray (high-energy photon ) with zero mass β = a beta particle α = a alpha particle 12

13 1-3 Big Bang Genesis of the Elements Within T = 10 9 K: T 1/2 ( 1 n ) = 11.3 min Hydrogen-Burning: Matarial gathers together into galactic clusters T = K: 1-3 Big Bang Genesis of the Elements In more massive Stars T > K: Carbon-Nitrogen still higher T: I guess, you got the idea 13

14 1-3 Big Bang Genesis of the Elements And last but not least Cosmic Abundance of the Elements log 10 / V nuclear stability most stable near Z = 26 have a close look at what is considered rare & precious see what we are made off atomic number / Z 1-4 Nuclear Reactions & Reactivity Stable Isotopes F only has one stable isotope: 19 F H 1 H 1 H Cl has two stable isotopes: 35 Cl (nat. abd.: 75.77%), 37 Cl (24.23%) 3 H and 14 C are constantly formed (cosmic rays, low conc.) Z = 26 stable zone, heavier elements (Z>=40) may have isotopes with long half-lifes, e.g., 40 K 1.25 x 10 9 y β (1.32 MeV) or 234, 235,238 U man-made elements (Transuranics) such as Np and Pu via Bombardment of one element with nuclei of another, e.g., n + U folowed by release of β 14

15 1-4 Nuclear Reactions & Reactivity α = a alpha particle (He nucleus) Alpha particles (Ernest Rutherford, England 1899) are a type of ionizing radiation ejected by the nuclei of some unstable atoms. They are large, heavy subatomic fragments consisting of 2 protons and 2 neutrons ( 4 2 He). Why? With increasing atomic mass, ratio of neutrons to protons increases from 1:1 to 1.6:1 for U. When the ratio of neutrons to protons in the nucleus is too low, certain atoms restore the balance by emitting alpha particles. Relative Abundance of Uranium Isotopes Isotope 238-U 235-U 234-U Nat. Abundance (%) Half-life (years) 4.47 billion 700 million 246, Nuclear Reactions & Reactivity β = a beta particle (e ) Beta Particles (Henri Becquerel, 1900) are equivalent to electrons. The difference is that beta particles originate in the nucleus and electrons originate outside the nucleus. Why? Beta particle emission occurs when the ratio of neutrons to protons in the nucleus is too high: an excess neutron transforms into a proton and an electron. The proton stays in the nucleus and the electron is ejected energetically. -> a new element is born! Beta emitters are: 99 Tc ( 99 Ru) or 60 Co ( 60 Ni) or 3 H ( 3 He) 15

16 1-4 Nuclear Reactions & Reactivity γ = a gamma ray (high-energy photon ) with zero mass Gamma Rays (Henri Becquerel 1896) have no mass and no electrical charge; they are pure electromagnetic energy (10,000 times as much energy as the photons in the visible) gamma photons travel at the speed of light and can cover hundreds to thousands of meters in air before spending their energy Why? Gamma radiation emission occurs when the nucleus of a radioactive atom has too much energy (often follows the emission of a beta particle). E.g.: 137 Cs β + ( 137 Ba)* γ Ba 1-6 History of Inorganic Chemistry 3000 BC gold copper silver tin antimony lead 1500 BC colored glasses & ceramic glazes made from SiO 2 and MOx iron 16

1-6 History of Inorganic Chemistry Anno Domini Alchemy Simplified, the aims of the alchemists were threefold: to find the Stone of Knowledge (The Philosophers' Stone), to discover the medium of

17 1-6 History of Inorganic Chemistry Anno Domini Alchemy Simplified, the aims of the alchemists were threefold: to find the Stone of Knowledge (The Philosophers' Stone), to discover the medium of Eternal Youth and Health, and to discover the transmutation of metals. To the medieval alchemist s mind the different elements were but the same original substance in varying degrees of purity. Gold was the purest of all and silver followed closely. 1-6 History of Inorganic Chemistry Anno Domini Various alchemical symbols used to denote elements until the 18th Century antimony arsenic bismuth copper gold iron lead magnesium mercury phosphorous platinum potassium silver sulfur tin zinc 17

1-6 History of Inorganic Chemistry Anno Domini In the 18th century scientists tried to pry loose

science and magic. Discovery of Hydrogen (1766) Henry Cavendish 1731 1810 A. L.

are well-established: I began to look about and write down the elements with their atomic weights

soon convinced me that the properties of elements are in periodic dependence upon their atomic

18 1-6 History of Inorganic Chemistry Anno Domini In the 18th century scientists tried to pry loose the real achievements in chemistry, pharmacology and medicine from this confusing cornucopia of science and magic. Discovery of Hydrogen (1766) Henry Cavendish A. L. de Lavoisier History of Inorganic Chemistry By 1869 Concepts of atoms & molecules are well-established: I began to look about and write down the elements with their atomic weights and typical properties, analogous elements and like atomic weights on separate cards, and this soon convinced me that the properties of elements are in periodic dependence upon their atomic weights. --Mendeleev, Principles of Chemistry, 1905, Vol. II Dmitri I. Mendeleev (Born in Siberia 1834, 17 Feb ) 18

Phys. Chem., 1869, I,60. Dmitri I. Mendeleev s Periodic Table of the Elements (17 Feb.

19 1-6 History of Inorganic Chemistry By 1869 Concepts of atoms & molecules are well-established: Dmitri I. Mendeleev s Periodic Table of the Elements (17 Feb ) 1-6 History of Inorganic Chemistry By 1869 Concepts of atoms & molecules are well-established: I.I. Mendeleev, J. Russ. Phys. Chem., 1869, I,60. Dmitri I. Mendeleev s Periodic Table of the Elements (17 Feb ) 19

1-6 History of Inorganic Chemistry In 1913 In 1913 British physicist Henry Moseley confirmed earlier suggestions that an element's chemical properties are only roughly related to its atomic weight

20 1-6 History of Inorganic Chemistry In 1913 In 1913 British physicist Henry Moseley confirmed earlier suggestions that an element's chemical properties are only roughly related to its atomic weight (now known to be roughly equal to the number of protons plus neutrons in the nucleus). What really matters is the element's atomic number - the number of electrons its atom carries, which Moseley could measure with X-rays. Ever since, elements have been arranged on the periodic table according to their atomic numbers. 1-6 History of Inorganic Chemistry 20

Populating nucleon states. From the Last Time. Other(less stable) helium isotopes. Radioactivity. Radioactive nuclei. Stability of nuclei.

Populating nucleon states. From the Last Time. Other(less stable) helium isotopes. Radioactivity. Radioactive nuclei. Stability of nuclei. Nucleus: From the Last Time System of and neutrons bound by the strong force Proton number determines the element. Different isotopes have different # neutrons. Stable isotopes generally have similar number