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Drill #18 Jan. 8 & 9, 2013. Take your time, do your own work, and draw the Lewis structure for HCN. Now, tell me the shape of this molecule. Agenda. Molecular Geometry Quiz Review Practice Problems Review Worksheet – due on Friday!. Objectives.
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Drill #18 Jan. 8 & 9, 2013 • Take your time, do your own work, and draw the Lewis structure for HCN. • Now, tell me the shape of this molecule.
Agenda • Molecular Geometry Quiz • Review Practice Problems • Review Worksheet – due on Friday!
Objectives • For a complete listing of Midterm objectives, see the Midterm County Assessment Teacher’s Guide.
Topics Covered • Chapter 1 (Measurements) • Chapter 2 (Energy & Matter) • Chapter 3 (Atomic Structure) • Chapter 4 (Electron Configurations) • Chapter 5 (The Periodic Table) • Chapter 6 (Groups of Elements) • Chapter 7 (Chemical Bonding/Formulas) • Chapter 8 (Shapes of Molecules)
Practice Problem • Identify the number of protons, neutrons, and electrons in the following ion: 34Cl1-
Answer • 17 protons; 18 electrons; 17 neutrons
Practice Problem • Identify the number of significant figures in the following measurements: (a) 2.0045 meters; (b) 0.00045 seconds; (c) 8.00200 ms; (d) 4500 cm
4 rules for determining sig figs • Non-zero numbers are always significant • Zeros between non-zero numbers are always significant • Zeros that act as placeholders are not significant 0.0253 has 3 sig figs 4320 has 3 sig figs • All zeros at the end are significant when there is a decimal point after an integer 6.20 has 3 sig figs
Answers a) 5 b) 2 c) 6 d) 2
Practice Problems • Convert 254 cm to meters • Convert 60 mg to kg King Henry Does Usually Drink Chocolate Milk Base Kilo hecto deka UNIT deci centi milli
Answers • 2.54 m • 0.000060 kg
Practice Problem • Identify the number of protons, neutrons, and electrons in the following ion: 59Ni2+
Answers • 28 protons • 31 neutrons • 26 electrons
Practice Problem • Write the electron configuration using both sublevel notation and orbital diagram notation for sulfur.
Answer • 1s22s22p63s23p4
Practice Problem • Which atom has the larger atomic radius: Ca, Sr, or Ba? Why? • Which atom has the greatest ionization energy: Ca, Sr, or Ba? Why?
Answers • Barium (Ba) – largest radius • Calcium (Ca) – greatest ionization energy
Review • What is an isotope? • What is an ion?
Review • Isotope = atoms of a particular element contain the same number of protons but may have a distinct number of neutrons. • Ion = atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative charge.
Practice Problem • Write the electron configuration using sublevel notation for strontium (Sr).
Answer • 1s22s22p63s23p64s23d104p65s2
Practice Problem • Write the formulas for the following: (a) barium carbonate, (b) sodium phosphate, and (c) carbon tetrachloride
Answers • a) BaCO3 b) Na3PO4 c) CCl4
Review Question • Name the following compound: • Cu(BrO3)2
Answer • Copper(II) bromate
Homework • Complete page 1 of Review Sheet • Due on Thursday!