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ATOMS, MOLECULES, & IONS

ATOMS, MOLECULES, & IONS. Dalton: atomic theory Atomic Structure & Weights P. Table. Molecules & Compounds CMPDS: formula, name. Molecule/Cmpd. Molecule: nonmetal + nonmetal share e- = or un= sharing. Cmpd: metal + nonmetal

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ATOMS, MOLECULES, & IONS

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  1. ATOMS, MOLECULES,& IONS Dalton: atomic theory Atomic Structure & Weights P. Table Molecules & Compounds CMPDS: formula, name

  2. Molecule/Cmpd Molecule: nonmetal + nonmetal share e- = or un= sharing Cmpd: metal + nonmetal transfer of e- metal lose & nonmetal gains Law Mass Conservation Total mass not D in chem rxn. - total mass reactants = total mass pdts H2 + O2 -------> H2O 1.0 16.0 2.0 + 16.0 2.0 + 32.0 34.0 = 18.0 2 H2 + O2 ------> 2 H2O 2*2.0 + 32.0 2*18.0 36.0 = 36.0 Mass is neither created nor destroyed, but changes form

  3. Definite Composition Law: cmpd composed of elements in a fixed ratio by weight Fraction Mass: fraction each element contributes to total mass of cmpd % Mass: % mass each element contributes to total mass of cmpd % mass = fraction mass * 100 Multiply Proportions When 2 elements combine to give to diff. substances, the masses of elements that form molecule can be expressed as a simple whole # CO CO2 43% C 57% O 27% C 73% O

  4. Elements: simplist form of matter; only 1 kind of atom; p.table; not broken down any further Compound: 2+ diff atoms bonded; fixed ratio by mass; properties diff than individual atoms; decomposed into simplier subst (chem) Mixture: 2+ diff subst; not chem react; mix in any diff amts; sep physical means

  5. TERMS Atomic Number: identifies which element # of protons Atomic Mass: relative ave mass of element including % of all isotopes Mass Number: atomic mass rounded to nearest whole number # protons + # neutrons Isotope: diff form of same element diff # of neutrons

  6. Greeks: 4 elements earth - air - water - fire Democritus - particles atomos Newton Dalton - atomic theory, 4 postulates pg42 1. All matter composed of identical atoms 2. Atoms that make up elements are diff diff. elements ---- atom make-up diff 3. Atoms neither created nor destroyed in chemrxns. Chemical rxns only involve change in atom ratios to produce new subst., not change in atoms themselves 4. Cmpds. are composed of diff atoms in fixed ratio

  7. Dalton’s theory explained laws of “……. definite composition” “……. conservation of mass (mattter)” ATOMIC STRUCTURE pg48 e-: -1.602*10-19 C p+: + 1.602*10-19 C Rutherford Au foil particleschargemasslocationdetermine p+, protons n0, neutrons e-, electrons element isotope chemistry 1 1 0 nucleus nucleus outside “1+” “0” “1-” p+ 1.0073 amu n0 1.0087 amu e- 5.486*10-4amu 1836 e- = 1 p+ mass

  8. ISOTOPE NOTATION p.table p.table mass # p+ + n0 +/- charge X atomic # # p+ # n0 mass# - atomic# p.table What info can you get Atomic #: Element: Symbol: Mass #: # n0 Notation with 2 less e-’s

  9. Element: Phosphorus Symbol: This is element # , therefore, it is Atomic # Mass #: # n0 Write notation with 3 more e-’s Now, try notation for O-15

  10. RELATIVE ATOMIC WEIGHT 20.1797 • NEON 3 Isotopes Isotope Mass % Abundance 19.9924356 20Ne 90.48 % 21Ne 0.27 % 20.9938428 22Ne 9.25 % 21.9913831

  11. + 19.9924356 20Ne 0.9048 = * 21Ne 20.9938428 0.0027 * = 22Ne 21.9913831 0.0925 * = 18.08915573 0.056683376 2.034202937 20.18004204

  12. particleschargemass p+, protons n0, neutrons e-, electrons “+” “0” “-” 1 1 0 ATOMIC MASS SCALE 1 amu = 1.66054*10-24 g 1 g = 6.02214*1023amu mole Atomic Weight H = 1.00794 = 1 He = 4.0026 = 4 Co = 58.9332 = 59 1 p+ 0 n0 2 p+ 2 n0 27 p+ 32 n0

  13. PERIODIC TABLE families, series, metal/nonmetal/metaloid last element not reactive; complete filled e- shell incr atomic # rows: periods/series columns: families/groups similar properties; same # valence e-

  14. ELEMENT CHARACTERISTICS nonmetal metal No luster or shine Not malleable Not ductile Forms molecules w/ each other or other elements Not conduct 20 elements Can form “+” & “-” charges Usually solids @ room temp Shine w/ luster, metallic luster Ductile: form into a wire, stretch when pulled Malleable: able to hammer (pound) into shape, deform w/o breaking Conducts heat & electricity Always “+” charge 70% of elements Form alloys w/ other metals Brass, Bronze Cu + Zn Cu + Sn metalloid Properties similar to metals & nonmetals Conduct electricity, semiconductor properties B, Si, As, Te, Ge, Sb

  15. MOLECULES/CMPDS molecules: 2+ diff atoms bonded together in any ration C2H6 C2H4 C2H2 diatomics: 2 of same atom combined 7: H, N, O, F, Cl, Br, I H2, N2, O2, F2, Cl2, Br2, I2 cmpds: combine +/- charged ion metal + nonmetal cation(+) anion(-) NOTICE: = opp charges, & diff charges Binary - 2 element cmpd; + metal & - non Na+1Cl-1 Mg+2O-2 NaCl MgO Sodium Chloride Magnesium Oxide Na+1O-2 Mg+2Cl-1 Na2O MgCl2 Sodium Oxide Magnesium Chloride

  16. REVIEW: Structure of an Atom 3 subatomic particles: p+; no; e- e- --> chemistry (E) p+ --> element no --> isotope Z: atomic number; # p+; i.d. element A: mass number; p+ + no N: # no; A - Z Atomic Symbol Isotope Notation FORMS: Potassium - 39 K - 39

  17. # p+ = # e- no charge to atom magnitude p+ charge = that of e- but “+” in sign ISOTOPE same element, same # p+, only change # no • Diff. make-up of same element • Not change element itself, same # p+ • Diff. # of n0 • Change atomic weight/mass result is change in Density ATOM ---charged Termed: ION Cation: + charged Anion: - charged # p+ > # e- “+” charge # p+ < # e- “-” charge same element, same # p+, only change # e-

  18. arranged atomic # • 7 rows; periods/series • 18 columns; groups/families PERIODIC TABLE elements in each group – similar chemical properties Groups numbered in 2 ways Group A/B Group 1 - 18 Group A/B Main Group “A” : first 2 col. left, last 6 col. rgt. Transistion Metals “B”: 10 col. in middlde Group 1 – 18 Each col. numbered 1 thru 18, left to right Inner Transition Metals (Rare Earth) Lanthanide Series; elements 58 - 71 Actinide Series; elements 90 – 103 14 col., notnumbered

  19. 1A : ALKALI METALS elements 1st col.: Li, Na, K, Rb, Cs, Fr Shiny, soft, low melting pt. React violently w/ H2O produce alkaline (or basic) Not found in pure state, combined w/ other elements in cmpd. 2A: ALKALINE METALS elements 2nd col.: Be, Mg, Ca, Sr, Ba, Ra shiny, silvery less reactive than 1A Not found in pure state

  20. 7A: HALOGENS (HALIDES) elements next to last col.: F, Cl, Br, I, At colored, corrosive nonmentals found combined w/ elements Halogen (HALS) - salt 8A: NOBLE GASES (INERT) elements last col.: He, Ne, Ar, Kr, Xe, Rn colorless gases, nonmetals low reactivity w/ other subst. INERT - nonreactive

  21. Diatomics Tetratomic: P4 Octatomic: S8 -- Se8 H2 -- N2 -- O2 -- F2 -- Cl2 -- Br2 -- I2 Polyatomic Ions: group of 2+ atoms covalently bonded together; net overall charge (+/-) Formula Types each diff element in subst. written in simplest form H2O2 --- HO Pb2(SO4)4 --- Pb(SO4)2 - PbSO Empirical actual # of each diff element in subst.; H2O2 Molecular Structural give relative manner in atoms are arranged in subst.; H—O—O—H

  22. pg58 Ionic or Covalent ???? Ionic: metal + nonmetal joined together to form an ionic cmpd. by forming an ionic bond Covalent: nonmetal + nonmetal joined together to form a covalent molecule by forming a covalent bond COMPOUND Binary: compound comprised of only 2 different elements Name: second element name ends in -ide Mg3N2 PCl3 Magnesium Nitride Phosphorus Trichloride

  23. IONIC CMPD Metal elements w/ only one positive charge Main group elements -- A columns Col. 1A -- +1 Col. 2A -- +2 Col. 3A -- +3 Ag +1 Zn +2 Regular 1st: name metal -- 2nd: single nonmetal, name with -ide ending NaCl -- Sodium Chloride Ba3P2 -- Barium Phosphide 2nd: name of polyatomic group (pg 62) AgNO3 -- Silver Nitrate Irregular Metal elements w/ more than one positive charge Transistion elements -- B columns Metal use name w/ charge, or, derived name lowest -ous highest -ic 1st: name metal, charge -- 2nd: single nonmetal, name with -ide ending FeCl2 -- Iron II Chloride FeCl3 -- Iron III Chloride Ferrous ” Ferric ” 2nd: name of polyatomic group Co(NO2)2 -- Cobalt II Nitrite

  24. CHEMICAL SYMBOLS HenotHE Na not NA H; Sn; W; He -- symbols are of 1 or 2 letters First letter is alwaysCAPITALIZED Second letter, if present, alwayslower case

  25. NOMENCLATURE & FORMULA WRITING Important components to always keep in mind are: 1. Oxidation numbers 2. Which are “+” & “-” ions 3. Ionic/Covalent 4. Binary or higher 5. Metal > 1 charge OXIDATION NUMBERS 1. “H” +1 except hydrides (-1) 2. “O”–2 except peroxides (-1); w/ “F” (+2) 3. “F” Fluorine, always -1 4. Metal always “+” joined w/ Nonmetal always “-” Nonmetal “-” charge based on # moves to end of row 5. Metals 1st Col. +1 2nd Col. +2

  26. Fe1Cl3 Fe1Cl2 BINARY COMPOUNDS Cmpds. containing 2 diff. elements A. IONIC CMPDS: Metal + Nonmetal 2nd: Element name, ending changed to “–ide” 1st : Name of element NaCl ___________ BaF2 ___________ Fe+3 Cl-1 Fe+2 Cl-1

  27. see list “on-line syllabus” Polyatomic Pattern -- Oxoanions no “O” 1 - O 2 - O 3 - O 4-O -ide hypo-root-iteroot-iteroot-ateper-root-ate -I -IO -IO2 -IO3 -IO4 iodidehypoioditeioditeiodateperiodate Acid hydro-root-ichypo-root-ousroot-ousroot-icper-root-ic HI HIO HIO2 HIO3 HIO4 HydroiodicHypoiodousIodousIodicPeriodic COVALENT MOLECULES Same pattern as Ionic Cmpds, but, use prefix to indicate # of each element present PREFIXES: tri: 3 tetra: 4 di: 2 mono: 1 penta: 5 octa: 8 nano: 9 hexa: 6 hepta: 7 deca: 10

  28. B. COVALENT MOLECULES (CMPDS) Nonmetal + Nonmetal 2nd: Element name, ending changed to “–ide” 1st : Name of element prefix only if subscript # > 1 always use prefix, even if subscript only 1 N2O __________ CO __________ CO CO2 Carbon Carbon P2S5 __________

  29. -ITE & -ATE ENDINGS -ite & -ate ending indicates the presence of “oxygen” -ite ending indicates 1 less “O” than –ate ending -ate ending indicates 1 more “O” than –ite ending

  30. MULTIPLE CHARGED METALS IRREGULAR METALS Metals w/ 2 or more charges Use: 1) Roman Numeral to indicate the charge 2) Derivative Name Copper I Copper II Cuprous Cupric Iron II Iron III Ferrous Ferric -OUS lowest charge -IC highest charge

  31. Fe2O3 FeO No subscripts +3 -2 -2 +2 Fe2 O3 Fe O charge “O”–2 = charge “Fe” +2 Charge on “Fe” = +3 Iron III Oxide Ferric Oxide Iron II Oxide Ferrous Oxide

  32. ACID NAMING PATTERN Based on the polyatomic ions “ate” & “ite” endings No “O” root- ic Hydro- HCl Hydrochloric Acid H2S Hydrosulfuric Acid H3P Hydrophosphoric Acid

  33. Halogen Acid Pattern F, Cl, Br, I 1 “O” 2 “O” 3 “O” 4 “O” -ClO3 -ClO2 -ClO4 -ClO Chlorite Hypochlorite Chlorate Perchlorate Perchloric Acid Chlorous Acid Chloric Acid Hypochlorous Acid -ITE Change ending to “OUS” -ATE Change ending to “IC”

  34. In a cmpd refers to WATER -- H2O HYDRATE : Calcium Sulfate Octahydrate Ca SO4. 8H2O Beryllium Hydroxide +2 -1 ( ) Be OH 2 Be OH 1 2 Metal w/ multiple charges (+1 or +2) Cu3(PO4)2 Copper II Phosphate Ion

  35. CO3 & Carbon Trioxide Carbonate Ion KF Potassium Fluoride Sn2(SO4)4 Tin IV Sulfate Sn(SO4)2 Sn(+4) & SO4(-2): Added subscripts (from the charges) are simplified in Ionic Cmpds The charge on SO4 times the subscript gives you the charge on Tin: 2 * |-2| = 4 Ferric Dichromate Lead II Bicarbonate Iron III Ammonium Silicate ZnO

  36. PO3-3 closer to F, more neg charge charge P + charge O = -3 We know O-2 Then P must be + P? + 3(O-2) = -3 P? = -3 - 3(O-2) P? = -3 – (-6) ? = +3 P+3

  37. EXCEPTIONS Exceptions O-2 O-1 H-1 Oxides Peroxides Hydride H2O Di Water NiH2 Hydrogen H2O2 Nickel II Hydride Li2O2 Lithium Li2O NaH Na2O2 Na2O Sodium Sodium Hydride K2O2 Potassium K2O Rb2O2 Rb2O Rubidium

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