1. Bell Work 12-3-15 What is the maximum number of electrons that can be in an atom’s 3 rd energy shell? a.2 b.18 c.24 d.8

2. Bell Work 12-3-15 What is the maximum number of electrons that can be in an atom’s 3 rd energy shell? a.2 b.18 c.24 d.8

3. Student Learning Objectives SPI 0807.9.1- Recognize that all matter consists of atoms. SPI 0807.9.4 - Differentiate between a mixture and a compound. SPI 0807.9.9 - Use the periodic table to determine the properties of an element. TOC: # Ch 12, Section 2 Notes Ionic Bonds

4. Forming Ionic Bonds Compounds that contain both __metals and __nonmetals__ are usually ionic. Ionic bonds will form when electrons are transferred from one atom to another atom. An atom is neutral because the number of electrons in an atom equals the number of protons. So, the charges cancel each other out. During the ionic bonding, one or more valence electrons are transferred from one atom to another. When an atom gains or loses electrons, it becomes a charged particle called an ion. Ionic bond = Ion formed Video

5. Ionic bonds form between a metal and a nonmetal. Atoms of most metals have few valence electrons and tend to lose these valence electrons and form positive ions. The valence level of nonmetal atoms is almost full. So, nonmetal atoms tend to gain electrons and become negative ions. When ions bond, they form a repeating three- dimensional pattern called a crystal lattice, such as the one shown below.

6. Ionic Bond - Electrons Transfer (Completely gives the electron away)

7. Octet Rule (add to bottom of your notes) Octet Rule: every atom wants to have eight valence electrons in its outermost electron shell. Atoms will gain or lose electrons to have a full outer shell (valence shell) Happy with 8 valence electrons in the outer shell!

8. The atoms that lose electrons form ions that have fewer electrons than protons. Because the positive charges outnumber the negative charges, these ions have a positive charge. Review: Forming Positive Ions

9. The atoms that gain electrons from other atoms during chemical changes have more electrons than protons. So, these have a negative charge. Oxygen atom gained 2 electrons in the second energy shell. Review: Forming Negative Ions

10. How does the bond between sodium & chlorine form? Cl   Na  Sodium has one valence electron. It’s looking to lose it Chlorine has seven valence electrons. It’s looking to gain one Electron Dot Diagrams only display the valence electrons.

11. How does the bond between sodium & chlorine form? Na Chlorine now has 17 protons & 18 electrons. It has a negative charge. Sodium now has 11 protons & 10 electrons. It has a positive charge. Cl   

12. Properties of Ionic Compounds (add to the bottom of your notes) Compounds that contain both metals and nonmetals are usually ionic. e.g. MgO High melting point – Don’t easily change to liquids (or gases) Solids → Poor conductors Liquids → Good Conductors Shatters when breaks

13. Ionic Compound (True or False) MgO SrCl 2 O 3 CH 4 O Review

14. Ionic Compound (True or False) MgO: True SrCl 2: True O 3: False CH 4 O: True Review

15. Elbow Partner: What is an ionic bond? Atoms will transfer one or more ________________ to another to form the bond. Each atom is left with a ________________ outer shell. An ionic bond forms between a ___________ ion with a positive charge and a ________________ ion with a negative charge.

16. Elbow Partner: What is an ionic bond? Atoms will transfer one or more ________________ to another to form the bond. Each atom is left with a ________________ outer shell. An ionic bond forms between a ___________ ion with a positive charge and a ________________ ion with a negative charge. ELECTRONS COMPLETE METAL NONMETAL

17. Ionic Bonding Worksheet Elbow Partners: Fill in the chart below

18. Ionic Bonding Worksheet Elbow Partners: Fill in the chart below

19. Digging Deeper: Ionic Bonds Activity Directions: Fill in the table

20. Exit Ticket How does an atom become a positive ion? How does an atom become a negative ion?