1. Monday, January 24, 2011 Do Now: Ionic bonds require gained or lost (exchanged) electrons. Covalent bonds involve shared electrons. Homework: Due tomorrow: pg. 207 #30-41 (chapter 7) Things to do: Review lesson steps Discuss homework that is due (Goldilocks Planet) Discuss Do Now Begin HW

2. Ionic and Covalent Bonding Ionic bonds require gained or lost (exchanged) electrons. Covalent bonds involve shared electrons. Review: electron dot structures

3. Homework pg. 207 #30-41 Due on Tues. Jan 25 Do you have a book? If not, you should copy the questions from this display (abbreviate to go faster) We’ll discuss answers briefly, and spend more time after writing the questions. PLEASE GIVE NAME, DATE, HOUR AND PAGE/ PROBLEM NUMBERS ON A PIECE OF NOTEBOOK PAPER… RIGHT NOW.

4. PG. 207 #30 DESCRIBE TWO WAYS THAT AN ION FORMS FROM AN ATOM. An ion forms when an atom gains or loses an electron.

5. Pg. 207 #31 State the number of electrons either lost or gained in forming each ion. A. Br- one electron is gained B. Na+ one electron is lost C. As 3- three electrons are gained D. Ca 2+ two electrons are lost E. Cu+ one electron is lost F. H- one electron is gained Ms. Gall’s summary: Each electron has ONE NEGATIVE CHARGE. A neutral atom has equal numbers of protons and electrons. When an electron is lost, the atom is left with more positive charges. When an electron is gained, the atom has extra negative charges.

6. Pg. 207 #32 Name each ion. Is it a cation or anion? A. Br- one electron is gained Bromine -, anion B. Na+ one electron is lost Sodium +, cation C. As 3- three electrons are gained Astatine 3-, anion D. Ca 2+ two electrons are lost Calcium 2+, cation E. Cu+ one electron is lost Copper +, cation F. H- one electron is gained Hydrogen -, anion

7. Pg. 207 #33 Define valence electron.

8. Pg. 207 #34 How many electrons does each atom have? What group is each in? A. nitrogen 7 electrons, group 15 B. Lithium 3 electrons, group 1 C. phosphorus D. Barium E. Bromine 35 electrons, group 17 F. Carbon

9. Pg. 207 #35 Write electron dot structures for each: A. Cl B. S C. Al D. Li

10. Pg. 207 #36 How many electrons must each atom lose to attain a noble- gas electron configuration? (Ms. Gall says… some “prefer” to GAIN electrons to make a stable valence shell octet. Since the question says – how many must it LOSE- I can simply give its number of electron dots.) A. Ca B. Al C. Li D. Ba Barium will LOSE 2 electrons; it’s found in column 2.

11. Pg. 207 #37 Write the formula for each ion formed when the element LOSES ITS VALENCE ELECTRONS> (Ms. Gall says- all the answers LOSE electrons; all will be positively charged.) A. aluminum, Al 3+ B. lithium C. barium D. potassium, K+ E. calcium F. Strontium, Sr 2+

12. Pg. 207 #38. DEEP THOUGHT ALERT! Why do nonmetals tend to form anions when they react to form compounds? Nonmetals are on the right side of the periodic table; they have a nearly full valence shell. It’s “easier” for them to gain a couple of electrons (become anions) than it is to LOSE that many electrons to empty out the valence shell.

13. Pg. 207 #39 What is the formula of the ion formed when the following elements gain or lose electrons and attain noble- gas configurations? A. sulfur S 2- B. sodium Na + C. fluorine F - D. phosphorus P 3-

14. Pg. 207 #40 How many electrons must be GAINED by each of the following atoms to achieve a stable electron configuration? A. N will GAIN 3 ELECTRONS B. S C. Cl D. P Ms. Gall says: subtract the number of electron dots from eight to get the answer. For example, N has 5 electron dots; 8-5 = 3. N will GAIN 3 electrons.

15. Pg. 207 #41 Which of the following pairs of atoms would you expect to combine chemically to form an ionic bond? (Ms. Gall says: if the atoms BOTH have 1,2, 6, or 7 valence- shell electrons (dots), then you can expect an ionic bond. If either has 3,4, or 5 valence electrons, it is likely to be a covalent bond. ) A. Li and S………… IONIC B. O and S……………. NOT IONIC C. Al and O………….NOT IONIC

16. Pg. 207 #41 Which of the following pairs of atoms would you expect to combine chemically to form an ionic bond? (Ms. Gall says: if the atoms BOTH have 1,2, 6, or 7 valence- shell electrons (dots), then you can expect an ionic bond. If either has 3,4, or 5 valence electrons, it is likely to be a covalent bond. ) D. F and Cl……….NON-BONDING (BOTH HAVE 7) E. I and K………..IONIC F. H and N……………NON-IONIC