Can matter be divided endlessly into smaller. which it can t be divided anymore?? Lecture outline: Chapter 2. The Atomic Theory of Matter

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1 Lecture outlie: Chapter 2 1. Atomic structure 2. The Periodic Table 3. Molecules ad ios 4. Namig ioic ad molecular compouds 1 ~400 B.C. Ca matter be divided edlessly ito smaller ad smaller pieces, or is there a poit at which it ca t be divided aymore?? 2 The Atomic Theory of Matter Joh Dalto: Each elemet is composed of atoms All atoms of a elemet are idetical. I chemical reactios, the atoms are ot chaged. Pb + S Compouds are formed whe atoms of more tha oe elemet combie. 3 Dalto s law of multiple proportios Atoms joi together i small whole umber ratios to make compouds C N C C Atoms ca combie i differet ratios to make differet compouds N N N 4

2 Atoms of Atoms of Compouds of Mixture of elemet 1 elemet 2 elemets 1 ad 2 elemets 1 ad 2 bservatios/studies of two pheomea were key to determiig the structure of the atom Electricity Separable charges are associated with matter Radioactivity Atoms are composed of subatomic particles 5 6 Three types of radiatio emitted from radioactive uraium Fu household sources of radioactivity Fiestaware (cirka 1970 ad earlier): the orage color comes from uraium salts () +2 α particle γ ray (+) 1 β particle Uraium source Later matles (Thorium) Electrically charged plates Detector 7 Smoke detectors (Americium) 8

3 Atomic Structure: compoets of the atom electros Charge: 1.60 x C (1) Mass: x g protos: foud i the ucleus, they have a positive charge equal i magitude to the electro s egative charge. Charge: x C (+1) Mass: x g eutros: foud i the ucleus, virtually same mass as a proto but o charge. Charge: eutral Mass: x g Atomic structure What are the subatomic particles, how big are they, ad how massive are they? ow do the subatomic particles associate i atoms? Plum puddig model: (icorrect) 9 10 The Rutherford experimet Iterpretatio of Rutherford s experimet +2 Alpha particle source Thi gold sheet Detector 11 12

4 The atom is mostly empty space, with the majority of the mass cocetrated i a small, dese regio Nucleus (proto(s) ad eutro(s) ~10 18 cm The electro is ~1000 times smaller i size tha the proto, but occupies a space ~10,000100,000 times greater tha the size of the ucleus electro: orbits the ucleus multielectro atoms have more tha oe e orbitig the ucleus Golf ball ucleus o 50 yard lie (2 cm diameter) ~10 13 cm Diameter of atom ~ 10 8 cm (~15 Å) 13 ow small is a atom??? The stadium ( 200 m diameter) represets the space i which the electro(s) reside! 14 Desity of a ucleus? Nucleus (proto(s) ad eutro(s) p+ p+ p+ p+ electro: orbits the ucleus Like forces repel, opposites attract, so What holds the ucleus together? Why do t the electros fall ito the ucleus?? Nucleus (proto(s) ad eutro(s) 15 p+ p+ p+ p+ electro: orbits the ucleus 16

5 Ma agitude of force ic creases Four basic attractive forces i ature Gravitatioal (masses) Electromagetic (electrically charged ad/or magetized) Weak uclear force Strog uclear force What defies the atoms of a sigle elemet? If all atoms cosists of protos, eutros, ad electros, the what makes oxyge oxyge ad carbo carbo? p+ p+ p+ p Elemets are classified o the basis of the umber of protos i the ucleus All atoms of a give elemet have the same umber of protos i the ucleus Elemets are classified o the basis of the umber of fprotos i the ucleus All atoms of a give elemet have the same umber of protos i the ucleus Z= atomic umber = # of protos i the ucleus Z= atomic umber = # of protos i the ucleus 19 20

6 ow may eutros ad electros i a give atom? #e =#p + # eutros ca vary Σ (# p + + # ) = mass # Atomic Symbols Mass umber A X Elemet Symbol Atomic umber Z 39K Mass umber 39 Elemet Symbol Atomic umber 19K Isotopes: atoms of a elemet that differ i the umber of eutros i the ucleus Carbo12 Two isotopes of carbo p+ p+ p+ p+ Carbo13 p+ p+ p+ p+ p+ p+ p+ p+ 6 protos 6 eutros 6 protos 7 eutros Isotopes have the same atomic umber but differet mass umbers 12 6C 13 6C 23 24

7 ydroge, the simplest elemet Silver has two isotopes: oe with 60 eutros, oe with 62 eutros. What are the mass umbers ad symbols of these isotopes? For silver (Ag), Z = A Z X Give the complete symbol for each of the followig atoms Sodium with 12 eutros For Na, Z = 11 argo with 21 eutros For Ar, Z = 18 Gallium with 39 eutros For Ga, Z = 31 ow may e, p + ad are preset i a atom of: 40 Ca See the Periodic 119 Table to fid the S atomic umbers for these elemets 244 Pu 27 28

8 Complete the followig table usig the Periodic Table ad the iformatio provided Symbol 46 Ti 127 Te What is the origi of the ame of the ucola beverage 7 up? # protos 45 # eutros Atomic # Mass # The Periodic Table Atomic weights: We will cover this material i lecture

9 The Periodic Table The Periodic Table orizotal rows = periods = 1,2,3,4,5,6,7 = 1 = 2 = 3 = 4 = 5 = 6 =7 = 6 33 = 7 34 The Periodic Table vertical colums = families or groups The Periodic Table Metals, metalloids, ad ometals = 1 = 2 = 3 = 4 = 5 = 6 =7 = 6 =

10 Alka li met als Alka alie earth met tals The Periodic Table Some importat group ames haloges Nob gas ble ses Elemets withi groups (families) have similar chemical properties The trasitio metals Elemets withi groups (families) have similar chemical properties Elemets Essetial for Life Chemical properties of alkali metals: react vigorously with water to produce hydroge gas React vigorously with oxyge to produce metal hydroxides React vigorously with haloges to produce salts Physical properties of alkali metals: Soft metal Silvercolored Low desity Low meltig ad boilig poits 39 40

11 Molecular ad ioic compouds 114 elemets by themselves = ~114 substaces (yaw) Glue differet elemets together i differet ratios ifiite umber of potetially iterestig compouds!! A molecule (molecular compoud; covalet compoud) A assembly of two or more ometal atoms, tightly boud (boded) together Molecules of a sigle atom Molecules of more tha oe type of atom Chemical formulas for molecules Molecular formula: the actual umbers of atoms of each elemet i the compoud Empirical formula: the simplest whole umber ratio of elemets i the compoud Some compouds caot be represeted by a molecular formula Allotropes of carbo: diamod, graphite, ad buckyball 43 Graphite, C diamod, C buckyball, C 6044

12 Structural formula A pictorial represetatio of a molecular formula. Shows how the atoms are joied together. Molecular formula: the umbers of atoms of each elemet i the molecule Structural formula: A pictorial represetatio showig how atoms are coected (arraged) i the compoud Perspective drawig: A structural t formula providig iformatio about the 3dimesioal shape of the molecule Ball ad stick model: A perspective drawig where boded atoms are show as balls ad sticks N 3 45 Space fillig model: A 3dimesioal model showig the relative sizes of idividual atoms ad their distaces from oe aother 46 Subscripts ad superscripts For a elemet, subscripts ad superscripts to the LEFT of the elemet idicate the atomic umber ad mass umber of that elemet P For a compoud, subscripts to the RIGT of the elemets tell us how may atoms of that elemet are preset i the compoud (o subscript = 1) Ios: atoms that have gaied or lost electros ad hece have a et egative or positive charge. The ucleus of the atom remais uchaged. Catios: electro(s) removed X + Aios: electro(s) added Y C 4, C 2 4, C 2, 2, N

13 Formatio of a sodium catio Formatio of a chloride aio Remove oe e add oe e 11 p+ 11 p+ 17 p+ 17 p+ 11 p + 11 p + 11 e 10 e Na Na 1+ = Na + 17 p + 17 p + 17 e 18 e Cl Cl Ios Metal atoms lose electros to form catios Nometal atoms gai electros to make aios WY?? May atoms gai or lose electros i order to obtai the same umber of electros as a earby oble gas + Li + N 3 2 F Na + K + Mg 2+ Ca 2+ Al 3+ P 3 S 2 S 2 Cl Br Rb + Sr 2+ Te 2 I Cs + Ba

14 Predict the charges o the ios formed by the followig elemets: Complete the followig table usig the Periodic Table ad the iformatio provided Symbol 85 Y 120 S Te Elemet earest oble gas io Na Mg Cs Ra F Cl N P Al C 53 # protos 65 # eutros # electros Atomic # 53 Mass # 127 Charge Biary ioic compouds Combiatios of metal catios ad ometal aios boded together through strog electrostatic attractive forces (a ioic bod ) Reactio of Na ad Cl Cotrast molecular compouds, which are formed from combiatios of ometals oly ( 2, C 2,C 4, etc.) boded by shared electro pairs i a covalet bod Combiatios of metalloids ad ometals are usually classified as molecular S. Esig, S. Atomic Esig, structure Chem. & 1210 omeclature 55 Ioic compouds are always represeted by empirical formulas: there is o discrete molecular formula for a ioic solid 56

15 Writig empirical formulas for ioic compouds A compoud with oly 2 elemets is a biary compoud For ioic i compouds, place the symbol for the metal before that of the ometal (catio first, aio secod) Subscripts after the elemets desigate the umber of atoms of that type i the compoud Whe writig the formula of a eutral ioic compoud, et charge = 0, so the charges must balace for each io Writig empirical formulas for ioic compouds A compoud with oly 2 elemets is a biary compoud For ioic compouds, place the symbol for the metal before that of the ometal (catio first, aio secod) Subscripts after the elemets desigate the umber of atoms of that type i the compoud Whe writig the formula of a eutral ioic compoud, et charge = 0, so the charges must balace for each io Writig empirical formulas for ioic compouds A compoud with oly 2 elemets is a biary compoud For ioic compouds, place the symbol for the metal before that of the ometal (catio first, aio secod) Subscripts after the elemets desigate the umber of atoms of that type i the compoud Whe writig the formula of a eutral ioic compoud, et charge = 0, so the charges must balace for each io Polyatomic ios: a compoud of two or more ometal atoms, joied through covalet bods, that forms a sigle charged uit (i.e., a molecular compoud that does ot have a eutral charge) S 3 is a molecular compoud S 4 2 is a polyatomic aio N 3 is a molecular compoud N 4+ is a polyatomic catio 4 p y 59 60

16 Commo polyatomic ios Name Formula Charge Ammoium io N Nitrate io N 3 1 Chlorate io Cl 3 1 Carboate io C Sulfate io S Ioic compouds cotaiig polyatomic ios Name Formula Charge X m Y Nitrate io N3 1 Ammoium io N Chlorate io Cl 3 1 Carboate io C Sulfate io S Peroxide io Phosphate io P Peroxide io Phosphate io P A fail proof way to write the correct formula for a ioic compoud X + Y m m Y m A fail proof way to deduce the io charges o ios preset i a ioic compoud + m X m Y X m Y X + Y m Reduce to a empirical i formula, if ecessary, by dividig idi by the appropriate iteger (e.g. Mg 2 2 Mg) 63 Be sure the magitude of the io charge matches what it should be based o positio i the periodic table for a moatomic io, or the kow charge for a polyatomic io 64

17 Write empirical formulas for the biary ioic i compouds formed from the combiatios of Co 2+, Mg 2+, ad Li + with S 2, P 3 4, ad S 2 4 Classify the followig compouds as ioic or molecular. Which molecular formulas are also empirical formulas? compoud Type? Empirical? NF 3 C 6 14 K 2 S P 4 S 3 Mg KBr F 2 As 3 XeF 2 NaF PbF 2 P 2 F Nomeclature: The amig of substaces Be able to ame: Costituet atoms i molecular compouds Costituet t ios i ioic i compouds Ioic compouds Molecular l compouds Acids Ioic compouds are amed usig a differet set of rules tha covalet compouds Namig ioic compouds Catio ame followed by aio ame So, how do we ame catios ad aios? 67 68

18 Namig moatomic catios (+ ios) Catios for which oly oe charge ca be formed (group 1A, 2A, 3A, some d block): the ame is simply the ame of the metal followed by io Catios of trasitio ( d block ) metals that ca form more tha oe charge: New method: Place the charge i paretheses after the metal ame ad before io old method for metals that form two charges: use root of lati ame + ous for lower charge, or ic for higher charge, followed by io Namig moatomic catios (+ ios) Catios for which oly oe charge ca be formed (group 1A, 2A, 3A, some d block): the ame is simply the ame of the metal followed by io Namig moatomic catios (+ ios) Catios of trasitio metals that ca form more tha oe charge: New method: Place the charge i paretheses after the metal ame ad before io old method for metals that form two charges: use root of lati ame + ous for lower charge, or ic for higher charge, followed by io There are t may polyatomic catios to worry about Commo polyatomic ios Name Formula Charge Ammoium io N Nitrate io N 3 1 Chlorate io Cl 3 1 Carboate io C Sulfate io S Peroxide io Phosphate io P

19 Namig moatomic aios ( ios) Drop the edig of the ame of the elemet ad add ide + io N 3 2 F S 2 Br There are a lot more polyatomic aios to worry about Makig sese of polyatomic aio ames Some of them also ed i ide ydroxide (kow this oe ow) Cyaide Peroxide azide Makig sese of polyatomic aio ames xyaios are very commo X m Elemets that form oly 2 oxyaios: Charges o both ios are geerally the same e with less oxyges = ite e with more oxyges = ate Elemets that form 3 or 4 oxyaios: Charges o both ios are geerally the same hypo = less per = more ydroge ios ( + ) ca combie with oxyaios to form ew hydroge oxyaios 75 76

20 Makig sese of polyatomic aio ames X m Note I am goig g to give you the formulas ad ames for the followig oxyaios o the exam iformatio sheet. At some poit you will eed to memorize these though. Formulas ad ames of commo polyatomic ios: Carboate io = C 2 3 Sulfate io = S 2 4 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate h io = P 3 4 Makig sese of polyatomic aio ames Elemets that form oly 2 oxyaios: Charges o both ios are geerally the same e with less oxyges = ite e with more oxyges = ate X m Formulas ad ames of commo polyatomic ios: Carboate io = C 3 2 Sulfate io = S 4 2 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate io = P 4 3 Nitroge combies with to form two commo oxyaios that have oe N: N 2 ad N 3 Sice we kow from the table that N 3 is the itrate io, we ca predict that N 2 is the itrite io Note the io charges o N 2 ad N 3 are the same (1 i each case) Makig sese of polyatomic aio ames Elemets that form oly 2 oxyaios: Charges o both ios are geerally the same e with less oxyges = ite e with more oxyges = ate X m Formulas ad ames of commo polyatomic ios: Carboate io = C 3 2 Sulfate io = S 4 2 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate io = P 4 3 Sulfur combies with to form two commo oxyaios that have oe S: S ad S 4 Sice we kow from the table that S 2 4 is the sulfate io, we ca predict that S 2 3 is the sulfite io Note the io charges o S 2 ad S are the same (2 i each case) 79 Makig sese of polyatomic aio ames Elemets that form oly 2 oxyaios: Charges o both ios are geerally the same e with less oxyges = ite e with more oxyges = ate X m Formulas ad ames of commo polyatomic ios: Carboate io = C 3 2 Sulfate io = S 4 2 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate io = P 4 3 Phosphorus combies with to form two commo oxyaios: P ad P 4 Sice we kow from the table that P 3 4 is the phosphate io, we ca predict that P 3 3 is the phosphite io Note the io charges o P 3 ad P are the same (3 i each case) 80

21 Makig sese of polyatomic aio ames X m Carbo combies with to form oly commo oxyaio with oe C: C 2 3 C 3 2 is the carboate io, ad there is o such thig as the carboite io Formulas ad ames of commo polyatomic ios: Carboate io = C 3 2 Sulfate io = S 4 2 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate io = P Makig sese of polyatomic aio ames Elemets that form 4 oxyaios: X, where X is a haloge (Cl, Br, I) ad = Formulas ad ames of commo polyatomic ios: 14 Carboate io = C 2 3 Sulfate io = S 2 4 Nitrate io = N 3 Perchlorate io = Cl 4 Phosphate io = P 3 4 Charges o all 4 ios are the same (1) Take the root of the haloge (chlor, bromo, iodo) ypo ite = X (e.g. hypochlorite) ite = X 2 (e.g. chlorite) ate = X 2 (e.g. chlorate) Per ate = X 4 (e.g. perchlorate) 82 xyaios ca also be formed with the formulas X p mp ad have ames that are ot easy to predict. You do ot eed to memorize or be familiar with ay of these for chemistry 1210 S is the thiosulfate io S is the dithioate t io S is the tetrathioate io There are a few oxyaios cosistig of metals combied with oxyges, boded similarly to the bods betwee ometals ad oxyges i oxyaios. You do t eed to memorize the ames of these ow, but here are a couple commo oes. M 4 = permagaate io (used widely i ge chem labs) Cr = dichromate io (also used widely i ge chem labs) 83 84

22 xyaio examples Elemets that form oly 2 oxyaios: Charges o both ios are geerally the same e with less oxyges = ite e with more oxyges = ate Elemets that form 3 or 4 oxyaios: Charges still the same hypo = less per = more ydroge ios ( + ) ca combie with oxyaios to form ew hydroge oxyaios X m Iformatio I will give you o exam Formulas ad ames of commo polyatomic ios: Carboate io = C 2 3 Nitrate io = N 3 3 Phosphate io = P 4 2 Sulfate io = S 4 Perchlorate io = Cl 4 + Ammoium io = N 4 You must kow the hydroxide io ( ) Namig ioic compouds: Catio Cti ame followed fll dby aio ame Examples: Name the followig ioic compouds: CaBr 2 Mg() 2 Co 2 3 Formulas ad ames of commo polyatomic ios: 2 Carboate io = C 3 Nitrate io = N 3 3 Phosphate io = P 4 2 Sulfate io = S 4 Perchlorate io = Cl 4 Ammoium io = N + 4 Acids A simple workig defiitio (for ow): a compoud that dissolves i water to produce hydroge ios ad a correspodig aio X TiCl 2 (N 4 4) 2 C 3 Na 2 S 4 NaS 4 Wherever possible, predict charges o simple catios ad aios based o positios i periodic table 87 88

23 Biary acids: Begi with hydro Namig acids X Follow hydro with aio ame, replacig ide with ic Complete the amig with acid Addig hydroges to oxyaios to form eutral acids: m + + X m m X Chage ite io to ous acid Chage ate io to ous acid Retai hypo or per if they are preset xyaio io Formula xyacid Formula Namig molecular compouds Nitrite io N 2 Nitrous acid N 2 Nitrate io N 3 Nitric acid N 3 ypochlorite io Cl 3 ypochlorous acid Cl chlorite io Cl 2 Chlorous acid Cl 2 Nometal + ometal May are biary chlorate io Cl 3 Chloric acid Cl 3 Perchlorate io Cl 4 Perchloric acid Cl 4 Carboate io C 2 3 Carboic acid 2 C 3 Sulfate io S 3 2 Sulfurous acid 2 S 3 Sulfate io S 4 2 Sulfuric acid 2 S 4 Phosphite io P 3 3 Phosphorous acid 3 P 3 Phosphate io P 4 3 Phosphoric acid 3 P

24 Namig biary molecular compouds: I geeral, the elemet closer to the metals is listed first the first elemet i the formula is amed first, usig it s ormal elemetal ame For the secod elemet i the formula, drop the edig of the elemet ame ad replace with ide Use prefixes to idicate the umber(s) of atom(s) i the biary compouds (do t use moo for 1st elemet) Moo Di Tri Tetra peta 93 Prefixes used whe amig biary molecular compouds Prefix Meaig moo 1 di 2 tri 3 tetra 4 peta 5 hexa 6 hepta 7 oa 8 deca 9 94 Namig biary molecular compouds: I geeral, the elemet closer to the metals is listed first the first elemet i the formula is amed first, usig it s ormal elemetal ame For the secod elemet i the formula, drop the edig of the elemet ame ad replace with ide Use prefixes to idicate the umber(s) of atom(s) i the biary compouds (do t use moo for 1st elemet) Name these molecular ad ioic compouds compoud Type? Empirical? Name NF 3 C 6 14 K 2 S P 4 S 3 Mg KBr F 2 As 3 XeF 2 NaF PbF 2 P 2 F

25 Give formulas for each of the followig ioic compouds a) Ammoium itrate b) Cobalt (II) itrate c) Nickel (II) sulfate d) Nickel (III) cyaide e) Vaadium (III) oxide f) Ammoium sulfate Formulas ad ames of commo polyatomic ios: 2 Carboate io = C 3 Nitrate io = N 3 3 Phosphate io = P 4 2 Sulfate io = S 4 Perchlorate io = Cl 4 + Ammoium io = N 4 97 Name the followig compouds: a) MgBr 2 b) Li 2 C 3 c) KS 3 d) KM 4 e) (N 4 ) 2 S f) CuCl g) CuCl 2 98 a) Carbo dioxide Give formulas for: b) Phosphorus s triiodide c) Sulfur dichloride d) Xeo trioxide e) Dioxyge difluoride Name the followig molecular compouds: a) N 2 F 4 b) Br c) SF 4 d) ClF 3 e) BCl 3 f) P