GENERAL CHEMISTRY PETRUCCI HERRING MADURA BISSONNETTE

http://www.thk.edu.tr/~eyilmaz/chem101/ GENERAL CHEMISTRY Principles and Modern Applications TENTH EDITION PETRUCCI HERRING MADURA BISSONNETTE Atoms and the 2 Atomic Theory PHILIP DUTTON UNIVERSITY OF WINDSOR DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY Slide 1 of 27 General Chemistry: Chapter 2

Atoms and the Atomic Theory CONTENTS 2-1 Early Chemical Discoveries and the Atomic Theory 2-2 Electrons and Other Discoveries in Atomic Physics 2-3 The Nuclear Atom 2-4 Chemical Elements 2-5 Atomic Mass 2-6 Introduction to the Periodic Table 2-7 The Concept of the Mole and the Avogadro Constant 2-8 Using the Mole Concept in Calculations Slide 2 of 27 General Chemistry: Chapter 2

2-1 Early Discoveries and the Atomic Theory Lavoisier 1774 Proust 1799 Dalton 1803-1888 Law of conservation of mass Law of constant composition Atomic Theory Slide 3 of 27 General Chemistry: Chapter 2

AgNO 3 K 2 CrO 4 Ag 2 CrO 4 FIGURE 2-2 Mass is conserved during a chemical reaction Total mass of substance is constant before and after reaction Slide 5 of 27 General Chemistry: Chapter 2

Dalton s Atomic Theory 1. Each element is composed of small particles called atoms. Atoms are neither created nor destroyed in chemical reactions. 2. All atoms of a given element are identical and differ from all other elements 3. Compounds are formed when atoms of more than one element combine in simple numerical ratios. Slide 9 of 27 General Chemistry: Chapter 2

If two elements form more than a single compound, the masses of one element combined with a fixed mass of the second are in the ratio of small whole numbers. Law of multiple proportions: In forming carbon monoxide, 1.0 g of carbon combines with 1.33 g of oxygen. In forming carbon dioxide, 1.0 g of carbon combines with 2.66 g of oxygen. Figure 2-3 Consequences of Dalton s theory Slide 10 of 27 General Chemistry: Chapter 2

2-2 Electrons and Other Discoveries in Atomic Physics Slide 11 of 27 General Chemistry: Chapter 2

FIGURE 2-5 Effect of a magnetic field on charged particles Slide 12 of 27 General Chemistry: Chapter 2

of 27 FIGURE 2-6 Cathode ray tube General Chemistry: Chapter 2

FIGURE 2-7 In 1897 Thomson -Electron m/e = -5.6857 10-9 g coulomb -1 Thomson concluded that CRs are negatively charged fundamental particles of matter found in all atoms. Cathode rays and their properties Slide 14 of 27 General Chemistry: Chapter 2

Figure 2-8 From 1906-1914 Robert Millikan showed ionized oil drops can be balanced against the pull of gravity by an electric field. The charge is an integral multiple of the electronic charge, e. Speculations about how the charged particles incorporated atoms result atom models Slide 15 of 27 Millikan s oil-drop experiment General Chemistry: Chapter 2

X-Rays and Radioactivity Radioactivity is the spontaneous emission of radiation from a substance. X-rays and g-rays are high-energy light. a-particles are a stream of helium nuclei, He 2+. b-particles are a stream of high speed electrons that originate in the nucleus. Slide 17 of 27 General Chemistry: Chapter 2

2-3 The Nuclear Atom Geiger and Rutherford 1909 Figure 2-11 The scattering of particles by metal foil Slide 19 of 27 General Chemistry: Chapter 2

Most of the mass and all of the positive charge is concentrated in a small region called the nucleus. There are as many electrons outside the nucleus as there are units of positive charge on the nucleus Slide 20 of 27 Figure 2-12 The -particle experiment General Chemistry: Chapter 2

Rutherford Model: Most of the mass and all of the positive charge of an atom centered in very small region called nucleus the rest is just empty space The magnitude of positive charge differ from atom to atom and the mass is half of the atomic weight of element There are same amount of electrons, equally number of nucleus charge, occupy the outside of the nucleus. The atom as a whole is electrically neutral. Slide 21 of 27 General Chemistry: Chapter 2

Rutherford protons 1919 James Chadwick neutrons 1932 Figure 2-13 The nuclear atom illustrated by the helium atom Slide 22 of 27 General Chemistry: Chapter 2

of 27 General Chemistry: Chapter 2

Scale of Atoms The heaviest atom has a mass of only 4.8 x 10-22 g and a diameter of only 5 x 10-10 m. Useful units: 1 amu (atomic mass unit) = 1.66054 x 10-24 kg 1 pm (picometer) = 1 x 10-12 m 1 Å (Angstrom) = 1 x 10-10 m = 100 pm = 1 x 10-8 cm Biggest atom is 240 amu and is 50 Å across. Typical C-C bond length 154 pm (1.54 Å) Slide 24 of 27 General Chemistry: Chapter 2

2-4 Chemical Elements To represent a particular atom we use symbolism: A= mass number Z = atomic number Slide 25 of 27 General Chemistry: Chapter 2

isotopes: Atoms have same atomic number but different mass number called isotopes. Ne Z=10 but A=20, 21, 22 Natural Abundance? Ions? Slide 26 of 27 General Chemistry: Chapter 2

2-5 Atomic Mass Weighted Average Atomic Mass of an Element Equation (2.3) fractional atomic fractional = abundance x mass of + abundance x of isotope 1 isotope 1 of isotope 2 atomic mass of + isotope 2 A ave = x 1 x A 1 + x 2 x A 2 + x n x A n where x 1 + x 2 + + x n = 1.0 Slide 27 of 27 General Chemistry: Chapter 2

Atomic Mass Unit(amu) Mass of 1/12 of 1 12C isotope is called 1amu Mass of all atoms are given with respect to 12C isotope. All mass number are not whole number except C-12 isotope. Slide 28 of 27 General Chemistry: Chapter 2

Determine Atomic Mass of Isotopes Figure 2-14 A mass spectrometer and a mass spectrum Slide 30 of 27 General Chemistry: Chapter 2

The Periodic Table Read atomic masses. Read the ions formed by main group elements. Read the electron configuration. Learn trends in physical and chemical properties. We will discuss these in detail in Chapter 9. Slide 31 of 27 General Chemistry: Chapter 2

Alkali Metals The Periodic table Noble Gases Alkaline Earths Halogens Main Group Transition Metals Main Group Slide 32 of 27 Lanthanides and Actinides General Chemistry: Chapter 2

2-7 The Concept of the Mole and the Avogadro Constant Physically counting atoms is impossible. We must be able to relate measured mass to numbers of atoms. buying nails by the pound or kilogram. using atoms by the gram Slide 33 of 27 General Chemistry: Chapter 2

Avogadro constant, N A The mole is an amount of substance that contains the same number of elementary entities as there are carbon-12 atoms in exactly 12 g of carbon-12. N A = 6.02214179 x 10 23 mol -1 Slide 34 of 27 General Chemistry: Chapter 2

of 27 Figure 2-17 One mole of an element General Chemistry: Chapter 2

General Chemistry Principles & Modern Applications 10 th Edition Petrucci/Herring/Madura/Bissonnette Chapter 2 Atoms and the Atomic Theory Dr. Wendy Pell University of Ottawa

When a match burns its mass increases. True or False, the only conclusion to be drawn here is that the Law of Conservation of Mass is incorrect? 1. True 2. False 3. Not sure? Slide 40 of 23

When a match burns its mass increases. True or False, the only conclusion to be drawn here is that the Law of Conservation of Mass is incorrect? 1. True 2. False 3. Not sure? Slide 41 of 23

After 10 gram sample of lithium metal is reacted in a closed container with 44.32 g of chlorine gas; 1.32 g of lithium remain, the chlorine is consumed completely. What mass of lithium chloride is formed? 1. 54.32 g 2. 8.68 g 3. 53.00 g 4. 55.64 g Slide 42 of 23

After 10 gram sample of lithium metal is reacted in a closed container with 44.32 g of chlorine gas; 1.32 g of lithium remain, the chlorine is consumed completely. What mass of lithium chloride is formed? 1. 54.32 g 2. 8.68 g 3. 53.00 g 4. 55.64 g Slide 43 of 23

Given the diagram of a to the right, which of the following diagrams are incorrect? - + 1. N S + 2. N S - - + - - + + 3. Both 1 and 2 are incorrect Slide 44 of 23

which of the following diagrams are incorrect? 1. N S + 2. N S - - + - - + + 3. Both 1 and 2 are incorrect Slide 45 of 23

Which of the following statements is incorrect using only the periodic table to the right. 1. Argon is the heaviest atom. 2. The heaviest element in group one is also the lightest element in period 3. 3. The lightest gaseous element is He. 4. The heaviest gaseous element is Cl 2. 5. The heaviest element in group 18 is also the heaviest element in period 1. Slide 46 of 23

Which of the following statements is incorrect using only the periodic table to the right. 1. Argon is the heaviest atom. 2. The heaviest element in group one is also the lightest element in period 3. 3. The lightest gaseous element is He. 4. The heaviest gaseous element is Cl 2. 5. The heaviest element in group 18 is also the heaviest element in period 1. Slide 47 of 23

To the right is a portion of the periodic table. Which of the following statements is correct? 1. Mg 2+, Al + and Si all have the same number of electrons. 2. H and He 2+ have the same mass. 3. Li +, Be 2+ and B 3+ all have the same number of electrons. 4. Li +, Be 2+ and B 3+ all have the same number of protons. 5. H, Li and Na all have the same number of electrons. Slide 48 of 23

To the right is a portion of the periodic table. Which of the following statements is correct? 1. Mg 2+, Al + and Si all have the same number of electrons. 2. H and He 2+ have the same mass. 3. Li +, Be 2+ and B 3+ all have the same number of electrons. 4. Li +, Be 2+ and B 3+ all have the same number of protons. 5. H, Li and Na all have the same number of electrons. Slide 49 of 23

Bromine has two naturally occurring isotopes, bromine-79 and bromine-81. Bromine exists as a diatomic compound, ie. Br 2. How many different Br 2 molecules are possible and what are their masses? 1. 2 different molecules: 158 and 162 u. 2. 3 different molecules: 158, 160, and 162 u. 3. 3 different molecules: 158, 159, and 160 u. 4. 4 different molecules: 158, 159, 160 and 161 u. 5. 4 different molecules: 158, 160, 161, and 162 u. Slide 50 of 23

Bromine has two naturally occurring isotopes, bromine-79 and bromine-81. Bromine exists as a diatomic compound, ie. Br 2. How many different Br 2 molecules are possible and what are their masses? 1. 2 different molecules: 158 and 162 u. 2. 3 different molecules: 158, 160, and 162 u. 3. 3 different molecules: 158, 159, and 160 u. 4. 4 different molecules: 158, 159, 160 and 161 u. 5. 4 different molecules: 158, 160, 161, and 162 u. Slide 51 of 23

Given the diagram below, which of the following statements is incorrect? 1. The ion marked A corresponds to m/z 204. 2. The ion marked A is lighter than the ion marked B. 3. The ion marked B corresponds to m/z 198. 4. The ion marked A is the lightest isotope of Hg. A B

Given the diagram below, which of the following statements is incorrect? 1. The ion marked A corresponds to m/z 204. 2. The ion marked A is lighter than the ion marked B. 3. The ion marked B corresponds to m/z 198. 4. The ion marked A is the lightest isotope of Hg. A B Slide 53 of 23

Without doing detailed calculations and using the periodic table to the right, which of the following contains the greatest number of atoms? 1. 1.0 kg of hydrogen gas (ie. H 2 ). 2. 1.0 kg of helium gas (ie. He). 3. 1.0 kg of water vapor (ie. H 2 O). 4. 1.0 kg of liquid water (ie. H 2 O). 5. 1.0 kg of nitrogen (ie. N 2 ). 6. 1 kg of Aluminium metal (i.e Al)

Without doing detailed calculations and using the periodic table to the right, which of the following contains the greatest number of atoms? 1. 1.0 kg of hydrogen gas (ie. H 2 ). 2. 1.0 kg of helium gas (ie. He). 3. 1.0 kg of water vapor (ie. H 2 O). 4. 1.0 kg of liquid water (ie. H 2 O). 5. 1.0 kg of nitrogen (ie. N 2 ).

Without doing detailed calculations and using the periodic table to the right, which of the following samples contain the least number of atoms? 1. 1.0 g of oxygen gas (ie. O 2 ). 2. 1.0 g of sulphur (ie. S 8 ). 3. 1.0 g of water vapor (ie. H 2 O). 4. 1.0 g of liquid water (ie. H 2 O). Slide 56 of 23

Without doing detailed calculations and using the periodic table to the right, which of the following samples contain the least number of atoms? 1. 1.0 g of oxygen gas (ie. O 2 ). 2. 1.0 g of sulphur (ie. S 8 ). 3. 1.0 g of water vapor (ie. H 2 O). 4. 1.0 g of liquid water (ie. H 2 O). Slide 57 of 23

Hg gas has a density of roughly 14 g ml -1. Without using a calculator, estimate the number of Hg atoms in a 100 ml sample. N A = ~6x10 23 mol -1 and the molar mass of Hg is ~200 g mol -1. 1. 10 22 atoms 10 23 atoms 2. 10 23 atoms 10 24 atoms 3. 10 24 atoms 10 25 atoms 4. 10 25 atoms 10 26 atoms 5. 10 26 atoms 10 27 atoms Slide 58 of 23

Hg gas has a density of roughly 14 g ml -1. Without using a calculator, estimate the number of Hg atoms in a 100 ml sample. N A = ~6x10 23 mol -1 and the molar mass of Hg is ~200 g mol -1. 1. 10 22 atoms 10 23 atoms 2. 10 23 atoms 10 24 atoms 3. 10 24 atoms 10 25 atoms 4. 10 25 atoms 10 26 atoms 5. 10 26 atoms 10 27 atoms Slide 59 of 23

The Snap Lake diamond mine in the North West Territories, Canada, is expected to produce 1.5 million carats of diamond per year. Given that naturally occurring diamond has density 0f 3.15 g cm -3 to 3.53 g cm -3 and 1 carat = 200mg, estimate, without using a calculator, the number of C atoms mined in the form of diamond per year. N A = ~6x10 23 mol -1 and the molar mass of C is ~12 g mol -1. 1. 10 27 atoms 10 28 atoms 2. 10 28 atoms 10 29 atoms 3. 10 31 atoms 10 32 atoms 4. 10 29 atoms 10 30 atoms 5. 10 26 atoms 10 27 atoms Slide 60 of 23

The Snap Lake diamond mine in the North West Territories, Canada, is expected to produce 1.5 million carats of diamond per year. Given that naturally occurring diamond has density 0f 3.15 g cm -3 to 3.53 g cm -3 and 1 carat = 200 mg, estimate, without using a calculator, the number of C atoms mined in the form of diamond per year. N A = ~6x10 23 mol -1 and the molar mass of C is ~12 g mol -1. 1. 10 27 atoms 10 28 atoms 2. 10 28 atoms 10 29 atoms 3. 10 31 atoms 10 32 atoms 4. 10 29 atoms 10 30 atoms 5. 10 26 atoms 10 27 atoms Slide 61 of 23