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Unformatted text preview: CHAPTER 2: ATOMS and MOLECULES ; Matter- is anything that has mass (~weight) and occupies space (has volume) * matter consists of elements 2 pure substances TABLE 2-1 p 26 Functions of Elements in Organisms 96% of living matter: 0, c, H and N Trace elements: required only in minute amounts Element (chemical symbol) a Phosphorus K Potassium S Sulfur Na Sodium Functions Required for cellular respiration; present in most organic compounds; component of water Forms backbone of organic molecules; each carbon atom can form four bonds with other atoms Present in most organic compounds; compo- nent of water; hydrogen ion (H "i is involved in some energy transfers Component of proteins and nucleic acids; component of chlorophyll in plants Structural component of bones and teeth: calcium ion (Ca2+) is important in muscle contraction, conduction of nerve impulses, and blood clotting; associated with plant cell wall Component of nucleic acids and of phospho- lipids in membranes; important in energy trans- fer reactions: structural component of bone Potassium ion (K") is a principal positive ion (cation) in interstitial (tissue) fluid of animals; important in nerve function: affects muscle con traction; controls opening of stomata in plants Component of most proteins Sodium ion (Now is a principal positive ion (cation) in interstitial (tissue) fluid of animals; important in fluid balance; essential for conduction of nerve impulses: important in photosynthesis in plants Needed in blood and other tissues of animals; activates many enzymes; component of chloro— phyll in plants Chloride ion (Cl') is principal negative ion (anion) in interstitial (tissue) fluid of animals; important in water balance; essential for photo- synthesis Component of hemoglobin in animals; acti- vates certain enzymes *Othcr elements found in very small (trace) amounts in animals, plants. or both include iodine (I), manganese (Mn). Copper (Cu). zinc (Zn). cobalt (Co), fluorine (F). molybdenum (Mm, selenium (Sc), boron (B). silicon (Si). and :1 few others. Marlon ATOMIC STRUCTURE Atoms are the smallest amount of an element that retains the chemical properties of that element Electron shell (energy level) consists of moving electrons in orbitals Atomic nucleus composed of protons and neutrons 3 m 5 Approximate Particle Charge Mass Location Proton Positive 1 amu Nucleus Neutron Neutral 1 amu Nucleus Electron Negative Approx. 1/1800 amu Outside nucleus NOTE: An atomic mass unit (amu or Dalton) is equal to the approximate mass of a single proton or a single neutron THE PERIODIC TABLE Atomic number = number of protons in the nucleus of an atom Symbol 6— C— . Ke . 3' Carbon — Name 1 _ Group 15 ME” 1211107 -—— Atomlc mass = number of protons + number of neutrons fin rm? 9! Hulhim man: Group 1 Group 2 Groq: 13 Group 14 Group 15 Group rs (Swap :7 3 r s s 1 a n 10 Li Be I3 C N O F Ne mum rm mun cum whom Ruins Mann fiflfl I ZISZ 108" Izflllfl mu IBM lens I!!! NJ"! II I? 13 Id’ I5 1? l? 19 Na Mg A] S: I-' 15' [:1 Ar Mm «iguana Mir-um slim Morin 5min chlorine mun 22"” ml “m Group 3 Group 4 camp 5 Group 5 Group 1 Group 8 Group El Group 10 Group II Group ‘2 mm in mm“ my” 1“ n1”! :5 a” in“! ID an 5! 12’ I?! :c 25 Eu :1 38’ 5‘ , so 51 u as 3| :5 30 K Ca 5c T] V Cr Mn Fe Co N] (,u Ln Czl (Jr;- As Se Br Kr mum cm w runn- mn moans Wu Il'M mm m ow All: can.“ urn-am unn'r. opium. arm Ilwa 39.09“ “1078 «356019 ‘73” WIS 51.09”. 51.935013 5531! m“ 30“ Sam m an 69.739 12.“ mum» mo NW! 83” n )8 M 0 II I? I! ll I! N If 13 fl :0 1| 1! a} §l Rh Sr Y Zr NI] Mo Tr. Ru Rh Pd Ag Cd In Sn SI: Tn I Xe will!“ m min“ Mn mm MM 1mm mil m Paladin!“ SM Cadmium lld‘llll Till ml IEIIIIM mus 1mm wars sun: was mm mane Us“ was: mm mm: an mm Imps: new mom "sun mm mm new 47 um 55 56 51 '12 33 '1‘ '15 P6 1‘} ?8 T9 so 91 Q as 9-! 85 I5 Cs Ba La Hf Tn W Re Us [r P: Au Hg Tl Pb Bi Pu At Rn mun mm mm Han-m mourn lunger uranium mm mm “in. a,” m mm,“ M ah...“ m m m rams rs 1:132: 1m um mom raw mm mm mm 19mg Imp: a: mm an inn mu mama [mp mm {222; ff BO GI I01 I05 IN ID? 103 109 Ilfl Ill "2 VIN Er Ra Ag: Rf Db S Bll [15 M1 Um!" Uuu" Uub" L utl' nmm um... mm mm... mm... norm. mum MIle um: .. u”... ' Mpm u...........- ..... cm: rm 12:)! Li"! mu um um: W W' m rm: 1:": :2053’ 5mm: no and us worn "period sigma hyaraam ..r 1mm“ 2mka Mario-ml Lnoumms 'n lure-rt I999 True smream rill-acted lha'r dirwvm innnyuf 2001. ' $£€£W<W°MIYMW° )3 so no n: 51 e: 61 or so or a so m 71 Co. Pr Ntl Pm Sm 111.! Lid T IJ Dy H0 111' Tm Yb Lu ' maplnnuie namnimdajmma osm- Wm- rioodrmm Hm Semi-m manna man-n rum In mm mun mm m urn-mm Lawficfim 111.110 “mono "4H [IQ 1M 15‘” I935 159%“ 1151.50 Imaz 16739 169.9“ 2‘ 173.01 I'Nflfi'l' ! ll “WWI I "3"“ ““lm- in m n: I: in n: w 91 as on me It“ In: In! . Th Pa U Np Pu Am Cm Bk Cl' Es Fm Mr] No Lr l'JIIIIlli Harm llllllfll mm m Dlflm minim Glluillll fulfill!!! m mm mm“ “film i 211ml 294mm; mm ram W] 21:] [217! um um um um [as] (15v: mill The nlorniurlaises Noam 1N3 Iable mlect ll-e precis'on 01am!!! measurement: Waunlifleii in Ezmlmam morn olllrn nlnmanl's maul more or mosrcumman mu:qu n: raicmmmmiaugmur rm. mmamu masses mm mm murmu mm: puma IM ngm ul mo doslrml. ISOTOPES IsoTopes are aToms of The same elemenT wiTh differenT aTomic masses; lie. They have The same # of proTons and elecTr'ons buT # of neuTr'ons varies ATomic mass of an elemenT — is The average mass of The isoTopes (weighTed by Theil' r'elaTive abundance in naTur'e Carbon—1 2 (150) Carbon-14 Ugo) (6p, 6n) (5)0. 8”) 9 20!]? Thomson molly Education RadioisoTopes are unsTable isoTopes ThaT decay and emiT radiaTion (8.9. carbon-14) ELECTRON CONFIGURATIONS ElecTron COHflgUf‘G‘l‘thS show The disTribuTion of elecTr'ons in an aTom's elecTr'on shells Hydrogen 2 Atomic number Helium lH He \2He F‘rs‘ Atomic mass 4-00 Element symbol -Q -. , \ / -\_ I, \_ She" j. Electron-shell — |_ \.._ . ' diagram x _,.r Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon al.‘ 439 53 50 7N 30 9F "3ND 59:03“ 43:5 .x;;‘;r\ ,/;":—‘:;~-_ g, :31: Ix}; \ 7:: l s e I I ._ . l.“ _ , \ . r, R I . H. ll I ll. J: \ j _ j_ 3:; / ~\_;_;_; My}: \;_ ;'/ x"; ; Sodium Magnesium Aluminum Silicon Phosphorus Sullur Chlorine Argon "Na 12”!) 13‘“ «Si 15" 183 we! is“? freak .e—o-n‘. Ira-H.“ / K ,J—ve J. H5.“ ,H Mar—9. / , \. _// .5 ‘\ ' I .\\ J: r H L ’ l.” t . . ' J/ . H‘X ’ , K“. mid r .r or: She" ’tl '9' l {| Wt l l “- o-‘If 1“. lil’ l‘o ill‘l" ‘l\‘.‘ "H l“ ‘?| "l 'l l ,H m ya m Ii l l m m in} it. 59'? "l EH \_ //z/ \ \\ .JI; ,' \_ W {fl '\ \"-. .1 f \‘ \-._ _ . ‘ K\'\'\_ 1']! I \ \x_ _ :19,» \\ A l/ ‘ {ii-j; 1,4 xxojj/x \\_+__’/ xito.’ / / \_' ’13; \.::_—:_'J., \Qttf/ valence elecTr'ons are elecTr'ons in The ouTer'l'nosT (2 valence) shell and The The mosT energeTic “The number of valence elecTr'ons deTer'mines an aTom's chemical properTies ATOMS FORM COMPOUNDS and MOLECULES Molecules form when Two or more aToms combine chemically Molecular formula STrucTural formula subscrist indicaTe The shows arrangemenT # of each Type of aTom of aToms Hydrogen (H2) H — H Oxygen (02) 0 = 0 WaTer (H20) c|l_ H H Compounds are H subsTances which conTain l 2 or more elemenTs MeThane (CH4) H—C—H Molecular mass = sum of The aTomic masses of The aToms in a single molecule eg. H20: (hydrogen: 2 X 1 amu) + (oxygen: 1 X 16 amu) = 18 amu Mole (mol) = aTomic mass of an elemenT or molecular mass of a compound, expressed in grams: one mole of any subsTance has 6.02 x 1023 uniTs (Avogadro’s #) eg. 18 g of waTer = 1mol waTer CHEMICAL REACTIONS Chemical equaTions describe chemical reacTions (361-11206 + 6 02 —> 6 C02 + 6 H20 + energy Elluuwc Li‘s-£31m i" gu'lwn LliUKlle' \'\.:'=.L'I‘ ReacTanTs parTicipaTe in The reacTion and ProducTs are The subsTances formed by The reacTion are wriTTen on The lefT side of The equaTion and are wriTTen on The righT side of The equaTion Reversible reacTions proceed simulTaneously in The forward direcTion and The reverse direcTion CO2 + H20 : H2CO3 : H+ + HCO; . _ '- 1 -- . .lc - .3: .. . , , Al» {.k‘czlmn Ram. (_.aal.r<>1m imagining“..- l. .. l (liH‘LJu-L‘ alx'ltl [Hi] Equilibrium is The poinT aT which The forward and reverse reacTions are proceeding aT The same raTe COVALENT BONDING In covalent bonds atoms share pairs of electrons and fill their valence shells o + =' 0 —~ . O i_ ' O I: H—y Hydrogen (H) Hydrogen (H) Molecular hydrogen (H2) or H—H (a) Single covalent bond formation. Two hydrogen atoms achieve stability by sharing a pair of electrons, thereby forming a molecule of hydrogen. In the structural tormula on the right, the straight line between the hydrogen atoms represents a single covalent bond. Jr ' ' 1 ['3' n\ , eo¢y\et+eo‘)’oo —> _ ..l’ ""0 7 .1" \‘- ._ . . Oxygen (0} Oxygen (O) Molecularoxygen {02) or 0:0 (double bond is formed) {b} Double covalent bond formation. In molecular oxygen, two oxygen atoms share two pairs of electrons, forming a double covalent bond. The parallel straight lines in the structural formula represent a double covalent bond, QWIIT ThurmmnHighel Educallnll Electron sharing in covalent compounds - Figure 2-5 p 32 POLAR and NONPOLAR COVALENT BONDS Electronegativity is a measure of an atoms attraction for electrons in chemical bonds (scale 0-4) Nonpolar covalent bonds form between atoms with similar electronegativities: electrons shared equally [a e H y”) hydrogen molecule: H2 oxygen molecule: 02 methane molecule: CH4 Polar covalent bonds form between atoms with different electronegativities - electrons pulled closer to more electronegative atom Oxygen part 6 u I a _ \ . . - I _- . . ' I _. Partial . ' I. Hydrogen parts _' .‘1 ) negative f ' O 0 l ‘J" O —p charge at Partial k. I ' ' oxygen end 0 . positive . .' ' ' of molecule \_ ' . .I' charge _ o o o ' . '_ at hydrogen Hydrogen (H) Oxygen (0) Hydrogen (H) end of molecule Water molecule (H20) Water is a polar covalent molecule: H20 - Figure2-7 p 34 ...
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This note was uploaded on 03/05/2010 for the course BIOL 1610 taught by Professor Jimblevins during the Spring '10 term at Salt Lake Community College.

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