430 likes | 590 Vues
Exam T Chapters 7 and 8 Review M 5 SL 110. Periodicity of First Ionization Energy (IE 1 ). Like Figure 8-18. Fig. 8.15. Identifying Elements by Its Successive Ionization Energies. Problem: Given the following series of ionization energies (in kJ/mol)
E N D
Exam T Chapters 7 and 8 Review M 5 SL 110
Periodicity of First Ionization Energy (IE1) Like Figure 8-18
Identifying Elements by Its Successive Ionization Energies Problem: Given the following series of ionization energies (in kJ/mol) for an element in period 3, name the element and write its electron configuration: IE1 IE2 IE3 IE4 580 1,815 2,740 11,600 Plan: Examine the values to find the largest jump in ionization energy, which occurs after all valence electrons have been removed. Use the periodic table! Solution:
Identifying Elements by Its Successive Ionization Energies Problem: Given the following series of ionization energies (in kJ/mol) for an element in period 3, name the element and write its electron configuration: IE1 IE2 IE3 IE4 580 1,815 2,740 11,600 Plan: Examine the values to find the largest jump in ionization energy, which occurs after all valence electrons have been removed. Use the periodic table! Solution: The largest jump in IE occurs after IE3 so the element has 3 valence electrons thus it is Aluminum ( Al, Z=13), its electron configuration is : 1s2 2s2 2p6 3s2 3p1
Ranking Elements by First Ionization Energy Problem: Using the Periodic table only, rank the following elements in each of the following sets in order of increasingIE! a) Ar, Ne, Rn b) At, Bi, Po c) Be, Na, Mg d) Cl, K, Ar Plan: Find their relative positions in the periodic table and apply trends! Solution:
Ranking Elements by First Ionization Energy Problem: Using the Periodic table only, rank the following elements in each of the following sets in order of increasingIE! a) Ar, Ne, Rn b) At, Bi, Po c) Be, Na, Mg d) Cl, K, Ar Plan: Find their relative positions in the periodic table and apply trends! Solution: a) Rn, Ar,Ne These elements are all noble gases and their IE decreases as you go down the group.
Suggested problems for Chapter 9 19, 20, 21, 22, 23, 25, 27, 29, 35, 37, 39, 43, 47, 49, 51, 53, 55, 56, 60, 62, 65, 79, 85, 93, 95, 96, 97 103, 105, 107
Chapter #9 - Models of Chemical Bonding 9.1) Atomic Properties and Chemical Bonds 9.2) The Ionic Bonding Model 9.3) The Covalent Bonding Model 9.4) Between the Extremes: Electronegativity and Bond Polarity 9.5) An Introduction to Metallic Bonding
Depicting Ion Formation with Orbital Diagrams and Electron Dot Symbols - I Problem: Use orbital diagrams and Lewis structures to show the formation of magnesium and chloride ions from the atoms, and determine the formula of the compound. Plan: Draw the orbital diagrams for Mg and Cl. To reach filled outer levels Mg loses 2 electrons, and Cl will gain 1 electron. Therefore we need two Cl atoms for every Mg atom. Solution: Mg + Mg+2 + 2 Cl- .. 2 Cl . .. .. .. . Cl Cl . .. .. .. .. Mg + Mg+2 + 2 Cl . .. ..
Depicting Ion Formation from Orbital Diagrams and Electron Dot Symbols - II Problem: Use Lewis structures and orbital diagrams to show the formation of potassium and sulfide ions from the atoms, and determine the formula of the compound. Plan: Draw orbital diagrams for K and S. To reach filled outer orbitals, sulfur must gain two electrons, and potassium must lose one electron. Solution: 2 K + 2 K+ + S - 2 S . .. . 2 - . .. .. .. .. .. K . + S 2 K+ + S K
Three Ways of Showing the Formation ofLi+ and F - through Electron Transfer
The Reaction between Na and Br to Form NaBr The Elements The Reaction!
Melting and Boiling Points of Some Ionic Compounds Compound mp( oC) bp( oC) CsBr 636 1300 NaI 661 1304 MgCl2 714 1412 KBr 734 1435 CaCl2 782 >1600 NaCl 801 1413 LiF 845 1676 KF 858 1505 MgO 2852 3600
Figure 9.10: The electron probability distribution for the H2 molecule.
Covalent bonds http://wine1.sb.fsu.edu/chm1045/notes/Bonding/Covalent/Bond04.htm animation http://www.chem.ox.ac.uk/vrchemistry/electronsandbonds/intro1.htm
For elements larger than Boron, atoms usually react to develop octets by sharing electrons. H, Li and Be strive to “look” like He. B is an exception to the noble gas paradigm. It’s happy surrounded by 6 electrons so the compound BH3 is stable. Try drawing a Lewis structure for methane.
Draw Lewis dot structures for the halogens. Notice that these all follow the octet rule! Try oxygen and nitrogen. These also follow the octet rule!
The Charge Density of LiF Fig. 9.20
Figure 9.12: Molecular model of nitro-glycerin. What is the formula for this compound?
Rules for drawing Lewis structures 1. Count up all the valence electrons 2. Arrange the atoms in a skeleton 3. Have all atoms develop octets (except those around He)
Make some Lewis Dot Structures with other elements: SiH4 H2O NH3 CH2O C2H6 C2H6O
CH3I Figure 9.9: Model of CHI3Courtesy of Frank Cox.
Make some Lewis Dot Structures with other elements: CH4 H2O NH3 CH2O C2H6 C2H6O
Rules for drawing Lewis structures 1. Count up all the valence electrons 2. Arrange the atoms in a skeleton 3. Have all atoms develop octets (except those around He) 4. Satisfy bonding preferences!