Charge Those Particles

1. Charge Those Particles Notebook: Create a new header page Find the Key Idea and write it down. Update your TOC

2. On a piece of scratch paper, answer the following “Quiz Questions”: Warm UpQuiz Which particle has a positive charge? Which particle has a negative charge? Which particle has no charge? Which particle(s) are “heavy” relative to the others? Which particle is relatively “mass-less” compared to the others? For the picture at the left, label the following: electron, neutron, proton, nucleus, s-shell, valence shell.

3. Procedure Take a careful look at Fig. 3.15 (a version of the Periodic Table). For each element, what information is given? Read the Introduction (p 125) and Read “Getting Charged”, page 127. Answer: the atomic number, and the electronegativity value Notice: most versions of the Periodic Table list the atomic mass, rather than the electronegativity. The electronegativity helps us determine whether a bond is likely to be covalent, polar covalent, ionic, or metallic.

4. Important Stuff • Flourine is the most electronegative element; it needs only 1 electron to achieve a stable electron configuration. • Why is it the “most” electronegative? Well, Flourine has fewer shells than the other elements in its family; the protons are “less shielded” so it attracts electrons more easily than it’s ‘family’. • A ‘family’ of elements is found in a vertical COLUMN of the periodic table. Another name for a column is a ‘group’. • Each ROW in the periodic table is called a… Period. • VERY IMPORTANT: the atomic number is the # of protons in an element. What pattern do you see for atomic numbers in Fig. 3.15?

5. PATTERNS What pattern do you see in the electronegativity values in Fig. 3.15? Write down the pattern in your notebook. Answer: The values increase as you move up and to the right. The Periodic Table is all about groupings and patterns. What pattern do you see for the atomic number in Fig. 3.15? Write down the pattern in your notebook. Answer: The values increase in the same pattern as we “read a book”; to the right, then starting over again on the next row (left to right).

6. More Stuff that matters • Remember: it’s the DIFFERENCE between electronegativity values of two elements which determines the type of bond that forms. • The smaller the difference, the more they are likely to “share” electrons. • Small differences in electronegativity often result in non-polar covalent bonds. • Medium differences often result in polar covalent bonds. • Large differences often result in ionic bonding. • This is not exact… chemistry is full of “exceptions to the rule”!

7. Questions from the Reading • The “Getting Charged” article tells you the sodium ion of charge 1+ ,(Na+), has 11 protons and 10 electrons. • Find sodium (Na) in the periodic table. What is it’s atomic number? • Now, find chlorine (Cl). What is it’s atomic number? • How many protons does Cl contain? • If Cl is neutrally charged, how many electrons does it have? • How many protons and electrons make up a chloride ion, Cl- ? Be careful here!  17 17 17 17 protons, 18 electrons

8. Day 2:Molecular Properties We’ve seen that some molecular properties, like conductivity and solubility, depend upon the type of bonding between molecules.

9. Stop and THInk In your reading, take a look at Figure 3.16 (page 128). This figure uses “chemical symbols” to show the process of a neutral sodium atom becoming a 1+ sodium ion. Take a look at it now. Any questions about this figure? You will need to use this procedure to answer Stop & Think Question #5. Now, answer Stop & Think Questions #1-5, page 128. Useful information: Potassium is K Calcium is Ca Flourine is F

10. Procedure: Ionization vs. Dissociation • Add new sub-section “Ionization vs. Dissociation” • Read Ionization versus Dissociation, p 129 Take notes as you read. • What is Ionization? • Use symbols to show the Ionization of Potassium (ex. Fig. 3.18) • What is Dissociation? • Use symbols to show the dissociation of Magnesium Chloride (MgCl2) in water

11. Ionization Vs. Dissociation • Make a Venn diagram to show the similarities/differences between ionization and dissociation • Low ionization energy: means it takes less energy to remove an electron (which means to create a positive ion). • High ionization energy: means it takes a lot more energy to remove an electron (which means it is happier to receive an electron, or to stay neutral…)

12. Ionization energy: the energy required to remove an electron from a neutral atom. “a measured value” Electronegativity: the ability of an atom in a molecule to take an electron. “a rating”

15. Procedure: Sharing Electrons • Add new subsection “Sharing Electrons” • Read Electronegativity, p 132 take notes as you read • p. 134 # 3a. Make a diagram to show how each pair of atoms shares or transfers electrons and determine the type of bond: • Hydrogen-oxygen in H2O • Carbon-oxygen in CO2 • Potassium-fluorine in KF • Carbon-hydrogen in CH4 • Bromine-bromine in Br2 • How does electronegativity relate to bond type? Use electronegativity values

16. Reflect & Connect (p. 135)

17. Day 4:Molecular Properties Read Sidebar: Water Works, p. 136 Read Sidebar: Mysterious Metals, p. 138 Skim Read (de-caffeination): What’s the Best Solvent, p. 143 Skim Read (drycleaning!): An Amazing Chemist, p 146