2-1 CHEM 100, Fall 2014 LA TECH Instructor: Dr. Upali Siriwardane Office: CTH 311 Phone Office Hours: M,W, 8:00-9:30 & 11:30-12:30 a.m Tu,Th,F 8: :00 a.m. Or by appointment Test Dates : Chemistry 100(02) Fall 2014 September 29, 2014 (Test 1): Chapter 1 & 2 October 20, 2014 (Test 2): Chapter 3 & 4 November 12, 2014 (Test 3) Chapter 5 & 6 November 13, 2014 (Make-up test) comprehensive: Chapters 1-6 9:30-10:45:15 AM, CTH 328

2-2 CHEM 100, Fall 2014 LA TECH REQUIRED : Textbook: Principles of Chemistry: A Molecular Approach, 2nd Edition-Nivaldo J. Tro - Pearson Prentice Hall and also purchase the Mastering Chemistry Group Homework, Slides and Exam review guides and sample exam questions are available online: and follow the course information links. OPTIONAL : Study Guide: Chemistry: A Molecular Approach, 2nd Edition- Nivaldo J. Tro 2nd Edition Student Solutions Manual: Chemistry: A Molecular Approach, 2nd Edition-Nivaldo J. Tro 2nd Text Book & Resources

2-3 CHEM 100, Fall 2014 LA TECH 2.1 Imaging and Moving Individual Atoms…………… Early Ideas about the Building Blocks of Matter…… Modern Atomic Theory and the Laws That Led to It… The Discovery of the Electron……………………… The Structure of the Atom…………………………… Subatomic Particles: Protons, Neutrons, and Electrons in Atoms……………………………………………… Finding Patterns: The Periodic Law and the Periodic Table………………………………………… Atomic Mass: The Average Mass Of an Element’s Atoms Molar Mass: Counting Atoms by Weighing Them………66 Chapter 2. Atoms and Elements

2-4 CHEM 100, Fall 2014 LA TECH Chapter 2. KEY CONCEPTS Atom Imaging Radioactivity Subatomic Particles Electrons Electronic Charge Nuclear atom Protons Neutrons Atomic number (Z) Size of Atoms Three chemical Laws Dalton's atomic theory Interpreting chemical formulas and chemical reaction. Isotopes Isotopic symbols Atomic Mass Units Mass Spectrometer isotope masses and % composition? Average atomic weights Periodic Table Abundance of Elements Earth's Atmosphere Concept of mole Gram to mole conversion

2-5 CHEM 100, Fall 2014 LA TECH Periodic Table Periodic table is an arrangement of all known element according to their atomic number and chemical properties.

2-6 CHEM 100, Fall 2014 LA TECH Development of Periodic Table Newlands - English Scientist 1864 – Law of Octaves – every 8th element has similar properties

2-7 CHEM 100, Fall 2014 LA TECH Who is Dmitri Mendeleev? Mendeleev, Dmitri ( ): Russian chemist Mendeleev, Dmitri ( ): Russian chemist Mendeleev is best known for Mendeleev is best known for his work on the periodic table; arranging the 63 known elements into a Periodic Table based on Atomic Mass

2-8 CHEM 100, Fall 2014 LA TECH Mendeleev’s Periodic Table the elements are arranged according to increasing atomic weights Missing elements: 44, 68, 72, & 100 Sc Ga Ge Tc Sc Ga Ge Tc Eight Groups: (IA,1B), (IIA,IIB), (IIIA,IIIB), (IVA,IVB), (VA,VB), (VIA,VIB), (VIIA,VIIB), (VIII), Twelve periods :

2-9 CHEM 100, Fall 2014 LA TECH Dimitri Mendeleev created this, the original, periodic table.

2-10 CHEM 100, Fall 2014 LA TECH Predicted Properties of Ekasilicon

2-11 CHEM 100, Fall 2014 LA TECH Modern Periodic Table the elements are arranged according to increasing atomic numbers

2-12 CHEM 100, Fall 2014 LA TECH Organization of Periodic Table Period Period – horizontal row Group –vertical column

2-13 CHEM 100, Fall 2014 LA TECH Modern periodic table H Li Na Cs Rb K TlHgAuHfLu Ba Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb Lr Ra ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC I A II A III A IV A V A VI A VIIA III B IVB VB VIB VIIB VIII B IB IIB Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es * + + *

2-14 CHEM 100, Fall 2014 LA TECH Information that may be in the table Ag Silver 47 Atomic number Name of the element Elemental Symbol Average Atomic mass

2-15 CHEM 100, Fall 2014 LA TECH Vertical columns- groups,families Horizontal columns- periods Elements in a group have similar chemical properties Group IA - alkali metal: Li, Na, K Rb, Cs, Fr Group IIA- alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra Group VIIA - Halogens: Cl, Br, I, At Group 0 - Noble gases: He, Ne, Ar, Kr, Xe, Rn

2-16 CHEM 100, Fall 2014 LA TECH A group or family He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es At Te As Si B I A II A III A IV A V A VI A VIIA 0 III B IVB V B VIB VIIB VIIIB IB IIB Groups are assigned Roman numerals with an A or B Groups are assigned Roman numerals with an A or B

2-17 CHEM 100, Fall 2014 LA TECH A row or period He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es At Te As Si B Periods are assigned numbers Periods are assigned numbers

2-18 CHEM 100, Fall 2014 LA TECH = Metal = Metalloid = Nonmetal Periodic Table: Areas

2-19 CHEM 100, Fall 2014 LA TECH Elemental states at room temperature He Rn Xe I Kr BrSe Ar Cl S Ne FO P N C H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es At Te As Si B Solid Liquid Gas * + * +

2-20 CHEM 100, Fall 2014 LA TECH The known elements 118 elements are currently known 89 are metals 31 are radioactive 22 are synthetic (all radioactive) 11 occur as gases 2 occur as liquids Let’s take a look at them on the table.

2-21 CHEM 100, Fall 2014 LA TECH Periodic Table of the Elements

2-22 CHEM 100, Fall 2014 LA TECH Family Names Group IAalkali metals Group IIAalkaline earth metals Group VIIAhalogens Group VIIIAnoble gases transition metals inner transition metals lanthanum seriesrare earths actinium seriestrans-uranium series

2-23 CHEM 100, Fall 2014 LA TECH What are these? Transition Metals Actinides Lanthanides Semimetals or Metalloids Ionic Charges Poly atomic ions and their charges

2-24 CHEM 100, Fall 2014 LA TECH Ion Charges He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es At Te As Si B Metals + Nonmetals -

2-25 CHEM 100, Fall 2014 LA TECH Periodic Law 1) What group or family to the following elements belong to? a) Na b) Ca c) Cl d) He

2-26 CHEM 100, Fall 2014 LA TECH 2) List two elements in each of the following: a) Main group elements b) Transition elements c) Lanthanides d) Actinides

2-27 CHEM 100, Fall 2014 LA TECH 3) Identify the following elements as either metals, non-metals, metalloids, noble gases, transition metals, actinides or, and lanthanides. a) Si b) Ca c) Cl d) Eu e) Pu f) Ni g) Ar

2-28 CHEM 100, Fall 2014 LA TECH 4) Which of the following are main group elements? a) Si b) Ca c) Cl d) Eu e) Pu f) Ni g) Ar

2-29 CHEM 100, Fall 2014 LA TECH The atomic symbol & isotopes Isotopic symbol: atomic symbol showing atomic number (Z) and mass number (A) Determine the number of protons, neutrons and electrons in each of the following. P3115 Ba U

2-30 CHEM 100, Fall 2014 LA TECH Isotopes *Atoms of the same element but having different masses. *All isotopes of an element have same atomic number * Each isotope has a different number of neutrons. Isotopes of hydrogenHHH Isotopes of carbon CCC

2-31 CHEM 100, Fall 2014 LA TECH Isotopes Most elements occur in nature as a mixture of isotopes. ElementNumber of stable isotopesElementNumber of stable isotopes H 2H 2 C 2C 2 O 3O 3 Fe 4Fe 4 Sn 10Sn 10 This is one reason why atomic masses are not whole numbers. They are based on averages.

2-32 CHEM 100, Fall 2014 LA TECH Complete the following table: ProtonsNeutronsElectrons Atomic Number Mass Number Atomic Symbol Isotopes & Atomic Mass (Weight)

2-33 CHEM 100, Fall 2014 LA TECH Atomic Structure of elemetns 5) What are isotopes?

2-34 CHEM 100, Fall 2014 LA TECH 6) How many isotopes does the elemental hydrogen, has? Give their symbols. Are they all these isotopes stable?

2-35 CHEM 100, Fall 2014 LA TECH 7) Naturally occurring carbon had two stable isotopes (carbon-12 and carbon 13) and an unstable isotope, carbon -14. Write isotopic symbols for a) carbon-12 b) carbon-13c) carbon-14: b) How many protons, neutrons, and electrons are in the carbon-12 isotope?

2-36 CHEM 100, Fall 2014 LA TECH 8) How many electrons, protons, and neutrons a 24 Mg 2+ isotope have?

2-37 CHEM 100, Fall 2014 LA TECH Finding Patterns: The Periodic Law and the Periodic Table 9) Order of elements in the modern periodic table is arranged according to atomic number. In his periodic table, Mendeleev used atomic weights not atomic numbers. a) In the periodic table what elements should have been swapped if Mendeleev was to following order of increasing atomic masses strictly? b) In the periodic table, Why is atomic masses approximately correlated with atomic number?

2-38 CHEM 100, Fall 2014 LA TECH Finding Patterns: The Periodic Law and the Periodic Table 9) Order of elements in the modern periodic table is arranged according to atomic number. In his periodic table, Mendeleev used atomic weights not atomic numbers. c) What is most directly involved in chemical reactivity: nucleus or the outermost electrons? d) Why do the elements in a group of the periodic table have similar chemical properties?

2-39 CHEM 100, Fall 2014 LA TECH Average atomic masses Most elements exits as a mixture of isotopes. Most elements exits as a mixture of isotopes. Each isotope may be present in different amounts. Each isotope may be present in different amounts. The masses listed in the periodic table reflect the world-wide average for each isotope. The masses listed in the periodic table reflect the world-wide average for each isotope. One can calculate the average atomic weight (AAM) of an element if the abundance of each isotope for that element is known. One can calculate the average atomic weight (AAM) of an element if the abundance of each isotope for that element is known.

2-40 CHEM 100, Fall 2014 LA TECH Masses of Atoms Carbon-12 Scale Masses of the atoms are compared to the mass of C-12 isotope having a mass of amu Atomic mass units (amu)

2-41 CHEM 100, Fall 2014 LA TECH Mass Spectrometer

2-42 CHEM 100, Fall 2014 LA TECH Mass Spectrum of Neon AAM(Ar) = [(90 x 20) + (10 x 22)] / 100 = 20.20

2-43 CHEM 100, Fall 2014 LA TECH Atomic Masses and Isotopic Abundances natural average atomic masses =  [(atomic mass of isotope)  (fractional isotopic abundance)]

2-44 CHEM 100, Fall 2014 LA TECH How do you calculate average Atomic Mass? M a x a + M b x b = AAM M a = mass of isotope a M b = mass of isotope b a = percent abundance of a a = percent abundance of a b = percent abundance of b b = percent abundance of b AAM = Average atomic mass (Reported on the Periodic Table) on the Periodic Table)

2-45 CHEM 100, Fall 2014 LA TECH Ma x a + Mb x b = AAM Ma = mass of isotope a Mb = mass of isotope b a = fractional abundance of a b = fractional abundance of b AAM = Average atomic mass (Reported on the Periodic Table) How do you calculate average Atomic Mass?

2-46 CHEM 100, Fall 2014 LA TECH Average atomic masses Example. Silicon exists as a mixture of three isotopes. Determine it’s average atomic mass based on the following data. Isotope Mass (u) Abundance 28 Si % 29 Si % 30 Si %

2-47 CHEM 100, Fall 2014 LA TECH Gallium in nature consists of two isotopes, gallium-69, with a mass of amu and a fractional abundance of 0.601; and gallium-71, with a mass of amu and a fractional abundance of Calculate the weighted average atomic mass of gallium. 1) M a x a + M b x b = AAM M a x a(%) + M b x b(%) 2) = AAM 100 Calculation

2-48 CHEM 100, Fall 2014 LA TECH M a ( 69 Ga ) = u, a = percent abundance of 69 Ga = x 100 M b ( 71 Ga ) = u, b = percent abundance of 71 Ga = x 10 We can obtain an equation with one unknown, AAM. AAM = x(0.601 x 100) x(0.339x100) AAM (Ga) = AAM (Ga) = = AAM (Ga) = u (amu) AAM Calculation

2-49 CHEM 100, Fall 2014 LA TECH Atomic Mass: The Average Mass of an Element’s Atoms 10) Silicon exists as a mixture of three isotopes. Determine its average atomic mass based on the following data to correct significant figure. IsotopeMass (amu or u) Abundance 28 Si % 29 Si % 30 Si %

2-50 CHEM 100, Fall 2014 LA TECH The Mole: The “Chemist’s Dozen” Definition of Mole Definition of Mole Molar Mass of a Compound Molar Mass of a Compound

2-51 CHEM 100, Fall 2014 LA TECH Chemistry is quantitative in nature; Its unit is the mole. The mole as unit vs. “dozen” as an unit The unit “dozen” is associated with 12 units. The unit MOLE is associated with 6.02 x units. There is Avogadro’s number of units in every mole x units is known as Avogadro’s number. 1 mole = 6.02 x units 1 mole of Cu atoms has an atomic mass of g, which is × Cu atoms, which is approximately 22 pennies. What is a mole?

2-52 CHEM 100, Fall 2014 LA TECH The Mole a unit of measurement, quantity of matter present Avogadro’s Number  particles Latin for “pile”

2-53 CHEM 100, Fall 2014 LA TECH Molar Mass Sum atomic masses (amu or g/mol) represented by formula atomic masses  gaw (g/mol) molar mass  MM

2-54 CHEM 100, Fall 2014 LA TECH Molar Mass: Counting Atoms by Weighing Them 11) What is a a) Mole b) gram-mole?

2-55 CHEM 100, Fall 2014 LA TECH 12) What is the mass in grams of a Cu atom? 13) An atom weighs 4.66 x g. What is the name of the element this atom belongs to?

2-56 CHEM 100, Fall 2014 LA TECH 14) What is the molecular mass (M.M.) of benzene (C 6 H 6 ) and how many grams are there in 1 more of benzene? 15) Find the formula weight (F.W.) of NaCl. 16) Determine the number of moles of CO 2 (M.M g/mol ) in 454 grams.

2-57 CHEM 100, Fall 2014 LA TECH 17) Determine the mass in grams of 3.60 mol of H 2 SO 4 (M.M 98.08). 18) Calculate the grams present in 3.40 x moles moles of Na 2 CO 3 (F.W ). 19) Determine the number of molecules of H 2 O in 3 moles H 2 O. 20) How many atoms are present in 17.0 mol of water?

2-58 CHEM 100, Fall 2014 LA TECH 19) Determine the number of molecules of H 2 O in 3 moles H 2 O. 20) How many atoms are present in 17.0 mol of water?

2-59 CHEM 100, Fall 2014 LA TECH 21) Given 5 moles of Sulfuric Acid having a formula of H 2 SO 4 answer the following questions: a) How many grams of Sulfuric Acid would this be? b) How many molecules of Sulfuric Acid would that be? c) How many Hydrogen atoms would be in this amount of Sulfuric Acid? d) How many Oxygen atoms would there be in this much Sulfuric Acid?

2-60 CHEM 100, Fall 2014 LA TECH 22) Given the chemical reaction: N H 2 ---> 2 NH 3, a) Write all more conversion factors in the chemical equation: b) Determine the moles of H 2 that will react with the 4 moles of N 2 c) Determine the grams of H 2 that will react with the 4 moles of N 2

2-61 CHEM 100, Fall 2014 LA TECH Example How many grams of Cu are there in 5.67 mol Cu? #g Cu = (5.67 mol)(63.546g/mol) = 360. g = 360. g Atomic mass of Cu

2-62 CHEM 100, Fall 2014 LA TECH Example Calculate the number of boron atoms in 1.000g sample of the element. #B atoms = (1.000g)(1mol / 10.81g)  (6.022  atoms/mol)  (6.022  atoms/mol) =  B atoms =  B atoms

2-63 CHEM 100, Fall 2014 LA TECH Example How many moles of silicon, S, are in 30.5g of S? #mol Si = (30.5g)(1 mol/32.06g) = mol Si = mol Si

2-64 CHEM 100, Fall 2014 LA TECH Example What is the molar mass of methanol, CH 3 OH? MM = 1(gaw) C + (3 + 1)(gaw) H + 1(gaw) O = 1(12.011) C + 4( ) H + 1( ) O = g/mol

2-65 CHEM 100, Fall 2014 LA TECH Example How many moles of carbon dioxide molecules are there in 6.45g of carbon dioxide? MM = 1(gaw) C + 2(gaw) O = g/mol #mol CO 2 = (6.45g)(1 mol/44.01g) = mol = mol

2-66 CHEM 100, Fall 2014 LA TECH Problem: You have inherited ¼ mole of pennies. If you spent 1 x dollars every second, how many decades would it take for you to spend your inheritance? Solution: ¼ mol x (6.02 x cents/1 mol) x ($1/100 cents) = 1.51 x dollars 1.51 x dollars x (1 sec/ 1 x dollars) x (1 min/60 sec) x (1 hr /60 min) x (1 day/24 hrs) x (1 yr/365 days) x (1 decade/10 yrs) (1 hr /60 min) x (1 day/24 hrs) x (1 yr/365 days) x (1 decade/10 yrs) = 4.79 decades = 4.79 decades Every mole contains 6.02 x units—that is a lot of pieces!!! How large is a mole?

2-67 CHEM 100, Fall 2014 LA TECH An element’s molar mass in grams per mole is numerically equal to the element’s atomic mass in atomic mass units. Mole & Mass Relationship

2-68 CHEM 100, Fall 2014 LA TECH To go from mass to units, you must go through the MOLE. [ Insert the scheme found at the top of pg 62 here]Element: Mass (g) / (1 mol/atomic mass (element)) = mole of element Mass (g) x (1 mol/atomic mass) x (6.02 x atoms/1 mole atoms) = # atomsMolecule/Compound: Mass (g) compound/molecular mass (compound) = mole of compound Mass (g) x (1 mol/molecular mass) x (6.02 x molecules/1 mol molecules) = molecules Mass-to-Mole Conversions

2-69 CHEM 100, Fall 2014 LA TECH How many Mg atoms are in g? Mg has an atomic mass of g/mol. Need to convert g Mg to moles of Mg g Mg x (1 mol/24.31 g) = 8.23 x mol Mg Now that you know the moles of Mg, you can determine the number of Mg atoms x mol Mg x (6.02 x atoms/1 mol Mg) = 4.95 x atoms Mg Mass-to-Mole Conversions

2-70 CHEM 100, Fall 2014 LA TECH Problem: How many grams of CO 2 are in 6.75 x molecules of CO 2 ? Strategy: 1. Need to know the molecular mass of CO Convert molecules of CO 2 to moles. 3. Convert moles of CO 2 to grams. Mole-to-MassConversions Mole-to-Mass Conversions

2-71 CHEM 100, Fall 2014 LA TECH Problem: How many grams of CO 2 are in 6.75 x molecules of CO 2 ? 1. CO 2 has a molecular mass of 44.0g/mol. There is 1 mole carbon in every mole of CO 2. 1 mole carbon = 12.0 g There are 2 moles oxygen in every mole of CO 2. 1 mole oxygen = 16.0 g Therefore, the molecular mass of CO 2 is: 1 x 12.0 g = 12.0 gfrom 1 mole C 2 x 16.0 g = 32.0 gfrom 2 mole O 44.0 gmass of 1 mole CO gmass of 1 mole CO 2 Mole-to-Mass Conversions

2-72 CHEM 100, Fall 2014 LA TECH Problem: How many grams of CO 2 are in 6.75 x molecules of CO 2 ? 2. Determine the moles of CO x molecules CO 2 x (1 mole CO 2 /6.02 x molecules) = 1.12 x moles CO 2 3. Determine the grams of CO x moles CO 2 x (44.0 g/1 mol CO 2 ) = 4.93 g Mole-to-Mass Conversions