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Notes One Unit Eight Molecules. Cross Word Answers State the three laws that support the existence of atoms List the five principles of Dalton's atomic theory. Calculate the masses of atoms in amu and gram units. Describe how the atomic mass unit was chosen. Calculate Average Atomic Mass
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Notes One Unit EightMolecules • Cross Word Answers • State the three laws that support the existence of atoms • List the five principles of Dalton's atomic theory. • Calculate the masses of atoms in amu and gram units. • Describe how the atomic mass unit was chosen. • Calculate Average Atomic Mass • Reading Assignment Two unit Two Next Class • http://www.teachersdomain.org/special/nova/nova.physics.ato/
Laws of proportions Definite Proportions • What is the proportion for(?)… • H2O • H2O2 • N2O3 • N2O5 • N2O • N2O4 Multiple Proportions 2:1 1:1 2:3 Multiple Proportions 2:5 2:1 1:2
Law of conservation of massDEMO NaOH/HCl phenolphthalein on a balance NaOH(aq)+ HCl(aq) H2O(l)+ NaCl(aq)
Law of conservation of mass 4 4 • 2H2(g) + 1O2(g)2H2O(l) • H= H= • O= O= • Mass is conserved! • 3H2(g) + 1N2(g)2NH3(l) • N= N= • H= H= • 2C2H6(g)+ 7O2(g) 4CO2(g) + 6H2O(l) • C= C= • H= H= • O= O= 2 2 2 2 6 6 4 4 12 12 14 8 + 6= 14
Three laws that support the existence of atoms 1. Law of definite proportions 2. E=MC2 3. Law of multiple proportions
List the five(Four?) principles of Dalton's atomic theory. • 1. All matter is made of indivisible and indestructible atoms. • 2. All atoms of a certain element are identical in mass and properties. • 3. Compounds can be formed by using two or more different kinds of atoms. • 4. A chemical reaction is a rearrangement of atoms.
Carbons Mass in amu and gram units • 1 amu=1/12 C-12 • 1 C-12 mass = 12.00000000 amu • 1amu = 1.66053X10-24 grams. • 12.0000000 grams/Mole!
Mass Spectroscope heating element negative grid Neon gas Ne Ne+1 e-1 beam 20Ne+1 21Ne+1 22Ne+1
Calculating Average Atomic Mass E amu% product C-12 98.90 = 1186.8 12.000000 x 13.003355 x = 14.3036905 C-13 1.10 1187 1187 98.90 % + 14.3 + 14 + 1.10 % 1201 100.00 % 1201 ÷100.00 = 12.01amu 4 sd 5 sd 4 sd
Notes Two Unit Two The Nucleus • Describe the evidence for the existence of electrons and their presence in atoms. • Explain how Rutherford's experiments led to the discovery of the nucleus. • Discuss atoms of different elements in terms of the numbers of electrons, protons, and neutrons they contain.
Magnet Face To Vacuum Pump Vacuum Chamber 39K+1 40K+1 41K+1 K+1 ions Photographic Plate K+1 To Vacuum Pump K e-1 Beam Potassium Gas- K(g)
Calculating Average Atomic Mass E amu% product 79Br 50.697 78.9183376 x = 4000.922961 = 3990.548738 80.9162913 x 81Br 49.317 4000.9 50.697% + 3990.5 +49.317% 7991.4 100.014 % 7991.4 ÷100.014 = 79.9028136 amu 5 sd 6 sd 5 sd = 79.903 amu
Cathode Ray Demo • Electrons(e-1) leave the cathode - + e-1 e-1 e-1 e-1 Cathode Anode
Van de Graff Demo Van de Graff generator Leyden Jar
Millikan's oil-drop experiment Charge of e-1 is equal to -1.602189 x 10-19 Coulombs. Oil drops perfume sprayer hole (+) plate -2 . -1 . X-ray . 0 battery (-) plate
Rutherford's experiments Alpha particle Lead Radium +2 8000 Microscope 7999 pass through 42He+2 Gold Foil 10,000 atoms thick +2 Characteristics of atoms mostly empty space Small(1/10,000), +79 dense, and heavy positive charge core
Atoms and their electrons, protons, and neutrons Proton(P+1) + Neutrons(n0)= Mass #(Z) 1 1 1 Hydrogen 0 H Hydrogen -1 1 1 Hydrogen 1 H Hydrogen -2 1 2 1 2 1 1 Hydrogen 1 2 H 3 Hydrogen -3 3 1 8 16 Oxygen -16 8 16 Oxygen 8 O 8 Iron Fe Iron -57 26 57 26 31 57 26
Nuclear Reactions A reaction, as in fission, fusion, or radioactive decay, that alters the energy, composition, or structure of an atomic nucleus. Fission: 235 U + 1 n 135 Xe + 100 Sr 1 + n 54 38 0 92 0 Fusion: 1 n+ 7 3 4 1 Li H + He + n 0 3 1 0 2 Decay: U 234 Th + 4 He 238 Alpha Decay 92 90 2 b Th 234 Pa + 0 234 Beta Decay(e-1) 90 91 -1
Notes Three Unit Eight The Structure of the Atom’s Shell • Describe the nature of light and how it is produced. • Explain how the wavelengths of light emitted by an atom provide information about electron energy levels. • Flame Tests Lab B
Atomic Model Rutherford model *Mostly Empty Space *Nucleus… Very Small, Very Dense, Positive Charged, Where were the electrons? What are the electrons doing? +
Particle Model of The Electron Neils Bohr e-1 found in the empty space. He used light to define their actions. e-1 region +
Electromagnetic Spectrum Visible Light Short wave gamma ray X-ray IR radar FM UV TV AM Short wavelength Long wavelength Low Energy High Energy
Bohr’s Model of the shell *Particle Model *Circular orbits * Hydrogen only e-1 Light’s Energy
The Spectroscope Prism slit Bright-line Emission Spectrum Helium Tube spectrograph
Solar Spectrum (92 elements) • hydrogen • helium • mercury • uranium
Spectrum Example #1 n=6 Violet indgo Blue Yellow Orange Red Green n=5 n=4 Excited State n=3 n=2 Quantum Amount n=1 Ground State energy
Spectrum Example #2 n=6 Violet indgo Blue Yellow Orange Red Green n=5 n=4 Excited State n=3 n=2 Quantum Amount n=1 Ground State energy
Spectrum Example #3 n=6 Violet indgo Blue Yellow Orange Red Green n=5 n=4 Excited State n=3 n=2 Quantum Amount n=1 Ground State energy
Spectrum Example #4 n=6 Violet indgo Blue Yellow Orange Red Green n=5 n=4 Excited State n=3 n=2 Quantum Amount n=1 Ground State energy
Identifying Elements with Flame Tests Na K Li Ba
Notes Four Unit Eight Electron Arrangements Forelements Compare the atomic models of Rutherford and Bohr. Describe the quantum mechanical interpretation of electrons in atoms. State Pauli's exclusion Principle, the aufbau principle, and Hund's rule, and describe their roles in determining the electron configuration of atoms.
Atomic Model Rutherford model Bohr model *Mostly Empty Space *Nucleus… Very Small, Very Dense, Positive Charged, Where were the electrons? What are the electrons doing? Quantum Amount +
De Broglie’s Wave model for Electrons • Wave Nature • Different solutions for e-1 actions. • e-1’s act as a particle or a wave. • e-1’s absorb or release Quantum Amount of NRG. • Demo of waves on a string
S Orbital y-axis z-axis X-axis
p Orbitals Shapes x-axis y-axis z-axis
p Orbitals Assembled y-axis z-axis x-axis
Electron Order of Filling Aufbau principle fill the lowest energy level first
Orbital Filling Diagram • Write the orbital filling diagram for Ne. • How many electrons does Ne have? • Final Answer • Short Hand Answer 10 e-1 1s 2 2s 2 6 2p attract 2s 2 6 [He] 2p
Orbital Filling Diagram • Write the orbital filling diagram for Na. • How many electrons does Na have? • Final Answer • Short Hand Answer 11 e-1 1s 2 2s 2 6 1 2p 3s 3s 1 [Ne]
Orbital Filling Diagram • Write the orbital filling diagram for Cl. • How many electrons does Cl have? • Final Answer • Short Hand Answer 17 e-1 1s 2p 3s 3p 2s 2 2 6 2 5 3s [Ne] 3p 5 2
Notes Five Unit Eight Electron Dot diagrams Quantum Numbers
Electron Dot Diagram for Neon 2s 2 6 [He] 2p ● ● Ne ● ● ● ● ● ●
Electron Dot Diagram for Sodium 3s 1 [Ne] Na ●
Electron Dot Diagram for Chlorine 3s 2 5 [Ne] 3p ● ● Cl ● ● ● ● ●