2 Outline - Chemistry Chapter Two Outline (Lecture)...

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Chemistry Chapter Two Outline (Lecture) Components of matter - Elements, Cmpds, Mixtures Atomic Structure Early Obs (three fundamental laws) (1) Mass conservation (mass is neither created nor destroyed and total mass of sub doesn’t ^ during rxn) (2) Definite composition (all samples of cmpd contain same elements with the same mass percent) (3) Multiple proportions (in two cmpds of the same elements the proportions will be in ratios of small whole numbers) Daltons Atomic theory (1) All matter is made up of atoms (indivisible particles of an element that cannot be created or destroyed consisting of p+, e-, n*) (2) Atoms of one element cannot be converted into atoms of another element (Nuc chem interconverts elements) (3) Atoms of an element are identical in mass and other props (Elements can have isotopes of diff masses) (4) Cmpds are formed by the chem combo of 2 or more elements in spec ratios Observations of Atomic Structure (the big three) Thomson 1897 Disc electron, measured the mass/^ ratio (Props of cathode rays) Milikan 1909 Measured the charge of the electron (oil drop) Rutherford 1910 disc tiny massive positive nucleus (alpha scattering) Current Atomic Theory A cloud of rapidly moving negatively charged electrons occupies most of the atomic volume and surrounds the tiny, central nucleus. The nucleus contains virtually all the mass of the atom and consists of positively charged protons and uncharged neutrons (Atomic diam= 10^-10m, nuclear diam 10^-14m) Particle Symbo l Charge Relative Charge Mass Relative Mass Proton P+ +1.602x10^- 1+ 1.673x10^- 1..007amu
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24g Neutron N* 0 0 1.675x10^- 24g 1.009amu Electron e- -1.602x10^- 19C 1- 9.109x10^- 28 5.486x10^- 4amu **AMU= one atom 12/6 C is exactly 12 amu Symbolic Representation (A/Z X) X=atomic symbol (element symbol) Z= atomic number= #p (=e- if neutral); atomic number deter identity of ele A= mass number = #p+ +#n* A-Z= #n* Isotope – atoms with same #p+, diff #n* Atomic mass- weighted average of masses of naturally occurring isotopes Periodic table- Organized in order of inc atomic number Periods (horizontal) Groups (vertical with similar chemical prop) A reps the main-group B reps transition metals 1A reps Alkali Metals (except H) 2A reps Alkaline earth metals 7A halogens 8A noble gases Metals = shiny solids (exc Hg) , malleable, conduct heat/electricity Nonmetals = gases or dull solids, poor conductors Metalloids= intermediate props Substance- matter whose composition is fixed Element- only one kind of atom Molecule- independent structural unit consisting of two or more atoms chemically bound Cmpd- two or more different elements that are chemically bound together. Elements are present in fixed parts by mass. Mixture- two or more substances physically intermingled whose parts
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This note was uploaded on 04/28/2008 for the course CHEM 1111 taught by Professor Robertparson during the Fall '08 term at Colorado.

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2 Outline - Chemistry Chapter Two Outline (Lecture)...

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