1. Chemical Bonding Chapter 12

2. Objectives O SPI 0807.9.2 Identify the common outcome of all chemical changes O SPI 0807.9.9 Use the periodic table to determine the properties of an element. O I can: 1. Describe how atoms bond to form compounds. 2. Identify the number of valence electrons in an atom. 3. Draw electron dot diagrams for atoms to show how valence electrons form bonds.

3. Chemical Bonding O Joining of atoms to form new substances O Formed by chemical changes O Form molecules O Properties of the new substances are different from the properties of the original elements O Atoms are held together by an interaction called a chemical bond O Formed when electrons are shared, gained, or lost 1. Ionic 2. Covalent 3. Metallic I can describe how atoms bond to form compounds.

4. Chemical Bonding O Valence electrons – electrons in the outermost energy level in an atom O Form bonds O Group number on the PT gives the number of valence electrons for each atom O Group 1: 1 valence electron O Group 2: 2 valence electrons O Group 3-12: 1 or 2 VE O Group 13: 3 VE O Group 14: 4 VE O Group 15: 5 VE O Group 16: 6 VE O Group 17: 7 VE O Group 18: 8 VE (He had 2 VE) I can identify the number of valence electrons in an atom.

6. Bonding O Atoms want 8 electrons in their outermost energy level O Atoms with less than 8 VE will more likely form bonds I can describe how atoms bond to form compounds.

7. How many valence electrons? 1. Sulfur O6O6 2. Magnesium O2O2 3. Helium O2O2 I can identify the number of valence electrons in an atom.

8. Electron-dot Diagrams O Model that shows only valence electrons in an atom 1. Write chemical symbol for atom. 2. Place 1 dot around symbol for every valence electron. 3. Place first 4 dots alone. 4. Pair up remaining electrons with dots. I can draw electron dot diagrams for atoms to show how valence electrons form bonds.

10. Draw electron-dot diagrams 1. Sodium 2. Phosphorous 3. Aluminum 4. Carbon 5. Chlorine 6. Calcium 7. Argon I can draw electron dot diagrams for atoms to show how valence electrons form bonds.

11. Objectives O SPI 0807.9.2 Identify the common outcome of all chemical changes O SPI 0807.9.9 Use the periodic table to determine the properties of an element. O I can: 1. Explain how ionic bonds form. 2. Explain how atoms become positively charged. 3. Explain how atoms become negatively charged. 4. Distinguish between ionic, covalent, and metallic bonds.

12. Ionic Bonds O Bond that forms when electrons are transferred from one atom to another O One or more valence electrons are transferred O Form by chemical changes O Molecules bonded by ionic bonds tend to have high melting and boiling points, conduct electric current, and soluble O Forms when a metal bonds with a nonmetal O Na + Cl O Mg + O O K + Cl I can explain how ionic bonds form. I can distinguish between ionic, covalent, and metallic bonds.

13. Ion O Charged particles O Gain or lose electrons O Protons NEVER change for an atom I can explain how ionic bonds form.

14. Forming Positive Ions O One atom loses electrons creating a positive ion. O Atom has more protons than electrons O Metals lose electrons O Energy is needed to lose electrons O Examples: O Na + O K + O Mg 2+ O Al 3+ O Ca 2+ I can explain how atoms become positively charged.

15. Forming Negative Ions O One atom gains an electron creating a negative ion O Atom has more electrons than protons O Nonmetals gain electrons O Energy is given off to gain electrons O The name changes when negative ions form O Change the ending of the name to –ide O Examples O Chloride Ion: Cl - O Oxide Ion: O 2- O Sulfide Ion: S 2- I can explain how atoms become negatively charged.

16. I can explain how ionic bonds form.

17. Objectives O SPI 0807.9.2 Identify the common outcome of all chemical changes O SPI 0807.9.9 Use the periodic table to determine the properties of an element. O I can: 1. Explain how covalent bonds form. 2. Identify which atoms will form covalent bonds. 3. Explain how metallic bonds form. 4. Distinguish between ionic, covalent, and metallic bonds.

18. Covalent Bond O Bond that forms when electrons are shared between atoms O Form by chemical changes O Molecules that are covalently bonded tend to have low melting and boiling points: why they are mostly gases. Solids are brittle. They do not conduct electric current and are not soluble. O Forms when a nonmetal bonds with another nonmetal O H + O → H 2 O O C + O → CO 2 O N + H → NH 3 I can explain how covalent bonds form. I can distinguish between ionic, covalent, and metallic bonds

19. The Simplest Molecules O Two or more atoms joined together in a definite ratio O Diatomic molecules – molecules made up of 2 atoms O Hydrogen (H 2 ) O Oxygen (O 2 ) O Nitrogen (N 2 ) O Fluorine (F 2 ) O Chlorine (Cl 2 ) O Bromine (Br 2 ) O Iodine (I 2 ) I can identify which atoms will form covalent bonds.

22. More-Complex Molecules Water Methane Glucose Acetaminophen I can identify which atoms will form covalent bonds.

23. Metallic Bonds O Bond formed by the attraction between positively charged metal ions and the electrons in the metal. O Metal ions form when metal atoms lose electrons O Outer most energy levels overlap allowing valence electrons to move freely throughout the metal O Allows metals to be reshaped O Malleability and ductility O Allows metals to be bent without breaking O Electrons are able to move around when metal is bent I can explain how metallic bonds form. I can distinguish between ionic, covalent, and metallic bonds.

24. I can explain how metallic bonds form.