Vanden Bout/LaBrake. ELECTRONS and BONDING WRAP. Important Information. EXAM REVIEW TUES 4PM Jester A 121A

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1 UNIT2DAY6-LaB Page 1 UNIT2DAY6-LaB Monday, October 08, :00 PM Vanden Bout/LaBrake CH301 ELECTRONS and BONDING WRAP UNIT 2 Day 6 Important Information EXAM REVIEW TUES 4PM Jester A 121A EXAM WEDNESDAY 7PM 9PM VandenBout (50335) UTC 2.102A version #1-200 VandenBout (50335) UTC 2.112A version #200+ LaBrake (50340) Welch version #1-250 LaBrake (50340) Welch version #250+ CH302 Vanden Bout/LaBrake Spring 2012

2 c) Each of these lasers shines on calcium UNIT2DAY6-LaB ( = 2.90 Page ev). 2 QUIZ: CLICKER QUESTION 1 Which of the of following is the electronic configuration for K and K +, respectively? a)1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 ; 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 a)1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 ; 1s 1 2s 2 2p 6 3s 2 3p 6 4s 1 a)1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 ; 1s 2 2s 2 2p 6 3s 2 3p 6 a)1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 ; 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Relate electron configuration to periodic table 1. A laser pulse shines for 10 s delivering a total energy of 4 mj of 633 nm light. Another laser delivers the same amount of energy with a wavelength of 408 nm. a) Which laser is delivering more photons to the sample? b) How much energy per photon (in units of ev) will be delivered for the red laser versus the blue laser? (1eV = x J)

3 What will happen when a 10 s pulse of the blue laser UNIT2DAY6-LaB Page 3 1. A laser pulse shines for 10 s delivering a total energy of 4 mj of 633 nm light. Another laser delivers the same amount of energy with a wavelength of 408 nm. a) Which laser is delivering more photons to the sample? b) How much energy per photon (in units of ev) will be delivered for the red laser versus the blue laser? (1eV = x J) c) Each of these lasers shines on calcium ( = 2.90 ev). What will happen when a 10 s pulse of red laser shines on calcium? What will happen when a 10 s pulse of the blue laser shines on calcium? QUIZ: CLICKER QUESTION 2 A laser pulse shines for 10 s delivering a total energy of 4 mj of 633 nm light. Another laser delivers the same amount of energy with a wavelength of 408 nm. Which laser is delivering more photons to the sample? A) RED Laser B) BLUE Laser C) BOTH ARE THE SAME D) NOT ENOUGH INFORMATION QUIZ: CLICKER QUESTION 3 and 4 Each of these lasers shines on calcium ( = 2.90 ev). What will happen when a 10 s pulse of red laser shines on calcium? a) NOTHING b) Electrons will be ejected c) Electrons will be ejected, but fewer than for the blue laser

4 What will happen when a 10 s pulse of red laser shines on calcium? a) NOTHING b) Electrons will be ejected c) Electrons will be ejected, but fewer than for the blue laser UNIT2DAY6-LaB Page 4 What will happen when a 10 s pulse of the blue laser shines on calcium? a) NOTHING b) Electrons will be ejected c) Electrons will be ejected, but there will be fewer than for the red laser 2. Please explain the change in effective nuclear charge, Z eff, as you move across a row in the periodic table from left to right. Indicate how this change in Z eff affects the ionization energy and the atomic radii of the atoms as you move across a row. Use the elements calcium and selenium as specific examples predicting which would have the smaller atomic nucleus and why.

5 a) [Ar]3s 2 3p 6 4s 2 3d 10 4p 2 b) [Ar] 4s 2 4p 2 c) [Ar] 4s 2 3d 10 4p 2 d) [Kr] 4s 2 3d 10 4p 2 e) [Kr] 4s 2 4p 4 UNIT2DAY6-LaB Page 5 EXPLANATION SPACE 3. Please write out the electron configuration for Germanium, Ge, using two different methods, the orbital notation (including using dashes and arrows, no noble gas shorthand), and the noble gas short hand method (don t need to use dashes and arrows, just superscript numbers will do). State the number of valence electrons in Ge. QUIZ: CLICKER QUESTION 5 Please write out the electron configuration for Germanium, Ge, using the noble gas short hand method

6 using the noble gas short hand method UNIT2DAY6-LaB Page 6 a) [Ar]3s 2 3p 6 4s 2 3d 10 4p 2 b) [Ar] 4s 2 4p 2 c) [Ar] 4s 2 3d 10 4p 2 d) [Kr] 4s 2 3d 10 4p 2 e) [Kr] 4s 2 4p 4 QUIZ: CLICKER QUESTION 6 Given that the correct electron configuration for Germanium, Ge is: [Ar] 4s 2 3d 10 4p 2 Which of the following sets of quantum numbers will not be an allowed set for an electron in the ground state of Ge? a) 1,0,0,½ b) 4,1,0,½ c) 3,1,1,½ d) 4,2,-2,½ e) 4,1,-1,-½ 4. Please draw the Lewis structure for the molecule, oxalate ion, C 2 O State whether or not you expect all the CO bond lengths to be the same or different, and explain your answer. Calculate the formal charge for each atom in the structure. The sum of the formal charges is what?

7 UNIT2DAY6-LaB Page 7 QUIZ: CLICKER QUESTION 6 Please draw the Lewis structure for the molecule, oxalate ion, C 2 O The formal charge for each atom in the structure is correct in which diagram? 5. Use a drawing and words to describe the differences between an ionic compound and a covalent compound on a molecular scale.

8 UNIT2DAY6-LaB Page 8 QUIZ: CLICKER QUESTION 7 The concept of electronegativity refers to: a)the notion that metals tend to lose electrons to form cations. b)the notion that nonmetals have a greater affinity for electrons, so will tend to form anions to achieve a noble gas type electron configuration. c)the notion that within the context of a covalent bond, an atom which has a stronger affinity for electrons will attract the shared pair to a greater extent. d)the notion that covalent compounds share their bonding pairs electrons equally between atoms producing pure covalent or non polar type bonds.

9 UNIT2DAY6-LaB Page 9 What have we learned? Electromagnetic radiation interacts with matter. Understanding EM radiation, helps to understand matter on the micro-scale. The physical model of the behavior of teeny tiny things is quite complicated and difficult to understand. The number of protons and the number and arrangement of electrons is important for predicting the chemical properties of the elements. You can abbreviate complicated electron configurations using a series of numbers and letters. The periodic table is your friend. You can name compounds. You can understand the structure of ionic compounds. You can predict basic bonding in molecules using Lewis structures.