1. Slide 1 of 39 © Copyright Pearson Prentice Hall Ions > Valence Electrons I. IONS A. Valence electrons: are in the highest occupied energy level of an atom. 1. number determines the chemical properties of an element. a. number of a representative element is its group number (A1-A8) 2. Octet Rule: In forming compounds, atoms tend to achieve the electron configuration of a noble gas. (Gilbert Lewis, 1916) 7.1

2. Slide 2 of 39 © Copyright Pearson Prentice Hall Ions > Valence Electrons Electron dot structures are diagrams that show valence electrons as dots. 7.1

3. Slide 3 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Cations 3. metals: tend to lose valence electrons, leaving a complete octet in the next-lowest energy level (cations form by this ionization) 7.1

4. Slide 4 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Cations a. Using electron dot structures to show ionization: 7.1

5. Slide 5 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Cations b. Group elements all form the same ionic charge i. Group 1A elements have a charge of 1+. ii. Group 2A elements always have a charge of 2+ iii. copper atom can ionize to form a 1+ cation (Cu + ). By losing its lone 4s electron it forms a psuedo noble gas configuration. 7.1

6. Slide 6 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Anions 4. non-metals: tend to gain electrons (anions are formed, see below) or share electrons with another nonmetal to form a complete octet. a. anion: an atom or a group of atoms with a negative charge. i. name of an anion typically ends in -ide 7.1

7. Slide 7 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Anions b. Groups have the same ionic charge: i. – indicates (1-) 7.1

8. Slide 8 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Anions c. dot representation of anion formation: d. halide ions (from group 7A). i. have seven valence electrons. ii. gain one electron to achieve the electron configuration of a noble gas. e. Oxygen group ions (Group 6A) i. gain two electrons 7.1

9. Slide 9 of 39 © Copyright Pearson Prentice Hall Ions > Formation of Anions 7.1

10. © Copyright Pearson Prentice Hall Slide 10 of 39 Conceptual Problem 7.1 7.1

11. © Copyright Pearson Prentice Hall Slide 11 of 39 Conceptual Problem 7.1 7.1

12. © Copyright Pearson Prentice Hall Slide 12 of 39 Conceptual Problem 7.1 7.1

13. © Copyright Pearson Prentice Hall Slide 13 of 39 Practice Problems Practice Problems For Conceptual Problem 7.1 Problem Solving 7.1 Solve Problem 1 with the help of an interactive guided tutorial. for Conceptual Problem 7.1

14. © Copyright Pearson Prentice Hall Slide 14 of 39 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section 7.1 Section Quiz. 7.1.

15. © Copyright Pearson Prentice Hall Slide 15 of 39 7.1 Section Quiz. 1. How many valence electrons are there in an atom of oxygen? a.2 b.4 c.6 d.8

16. © Copyright Pearson Prentice Hall Slide 16 of 39 7.1 Section Quiz. 2. Atoms that tend to gain a noble gas configuration by losing valence electrons are a.metals. b.nonmetals. c.noble gases. d.representative elements.

17. © Copyright Pearson Prentice Hall Slide 17 of 39 3. When a magnesium atom forms a cation, it does so by a.losing two electrons. b.gaining two electrons. c.losing one electron. d.gaining one electron. 7.1 Section Quiz.

18. © Copyright Pearson Prentice Hall Slide 18 of 39 4. When a bromine atom forms an anion, it does so by a.losing two electrons. b.gaining two electrons. c.losing one electron. d.gaining one electron 7.1 Section Quiz.

19. © Copyright Pearson Prentice Hall Slide 19 of 39 51 Physical Science P.12.A.2 http://www.rpdp.net/sciencetips_v2/P12A2.htmhttp://www.rpdp.net/sciencetips_v2/P12A2.htm Which of the following elements can form a 1- anion that contains 54 electrons? A. B. C. D.. From: http://www.doe.mass.edu/http://www.doe.mass.edu/

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