1. Chap 15: Ionic Bonding Do Not Write this Slide Standard: PS2D: Ions are produced when atoms or molecules lose or gain electrons, thereby gaining a positive or negative electrical charge. Ions of opposite charge are attracted to each other, forming ionic bonds. Chemical formulas for ionic compounds represent the proportion of ion of each element in the ionic array. Targets: Describe the ionic bond as the electrostatic attraction between oppositely charged particles. Describe how ions can be formed as a result of electron transfer. Predict whether a compound of two elements would be ionic from the position of the elements in the periodic table or from their electronegativity values.

2. Chap 15 & 16: Chemical Bonding Only one group of elements is stable (nonreactive). What is unique about their electron structure? Filled s & p sublevels All other elements react in order to achieve this stable electron configuration. Ionic Bond: Transfer of electrons; metal + nonmetal Covalent Bond: Sharing of electrons; nonmetal + nonmetal

3. Do not Write this Slide Observe Describe how ions can be formed as a result of electron transfer. Ions are formed when atoms gain or lose electrons Fluorine gains one electron to become the fluoride ion having a charge of -1 Lithium loses one electron to become the lithium ion having a charge of +1

4. Do Not Write this slide, Observe Describe the ionic bond as the electrostatic attraction between oppositely charged particles. The fluorine ion (fluoride) has a negative charge (F 1- ) The lithium ion has a positive charge (Li 1+ ) The bond is formed due to the electrostatic attraction between the opposite charges (1- and 1+)

5. How Ions are Formed Ions are formed when atoms gain or lose electrons Reaction between Sodium and Chlorine Sodium configuration: 1s 2 2s 2 2p 6 3s 1 or __ __ __ 1s 2s 2p 3s If Na loses one electron then it would end in 2s 2 2p 6 and be stable. Then sodium has 11 protons (11+), but only 10 electrons (10-) so it acquires a charge of 1+ and becomes the sodium ion, Na +. In order for it to lose an electron, something has to gain an electron

6. Describe how ions can be formed as a result of electron transfer. Ions are formed when atoms gain or lose electrons Reaction between Sodium and Chlorine Chlorine configuration: 1s 2 2s 2 2p 6 3s 2 3p 5 or __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p If Cl gains one electron then it would end in 3s 2 3p 6 and be stable. Then chlorine has 17 protons (17 + ), and 18 electrons (18 - ) so it acquires a charge of 1 - and becomes the chloride ion, Cl -. It will gain the electron from the sodium.

7. Reaction between Sodium and Chlorine Since opposite charges attract, the Na + and Cl - ions form an ionic bond. Structure: [Na] + [ Cl ] - Name: Sodium chloride Formula: NaCl

8. Describe how ions can be formed as a result of electron transfer. Ions are formed when atoms gain or lose electrons Reaction between Magnesium and Chlorine Magnesium configuration: 1s 2 2s 2 2p 6 3s 2 or __ __ __ 1s 2s 2p 3s If Mg loses two electrons then it would end in 2s 2 2p 6 and be stable. Then magnesium has 12 protons (12+), but only 10 electrons (10-) so it acquires a charge of 2+ and becomes the magnesium ion, Mg 2+. In order for it to lose two electrons, something has to gain two electrons

9. Ions are formed when atoms gain or lose electrons Reaction between Magnesium and Chlorine Chlorine configuration: 1s 2 2s 2 2p 6 3s 2 3p 5 or __ __ __ __ __ __ __ __ __ 1s 2s 2p 3s 3p If Cl gains one electron then it would end in 3s 2 3p 6 and be stable. Then chlorine has 17 protons (17 + ), and 18 electrons (18 - ) so it acquires a charge of 1 - and becomes the chloride ion, Cl -. Since chlorine can only gain one electron and magnesium gives up two electrons, magnesium requires two chlorine atoms.

10. Example Reaction between Magnesium and Chlorine Since opposite charges attract, the Mg 2+ and the 2 Cl - ions form an ionic bond. Structure: [Mg] 2+ [ Cl ] - 2 Name: Magnesium chloride Formula MgCl 2

11. Describe how ions can be formed as a result of electron transfer. Reaction between Potassium and Oxygen Student Practice – 1) Write the electron configuration for Potassium and Oxygen, 2) Write the charge for the loss or gain of electrons, 3) Write the Diagram 4) Formula and 5) Name. Potassium configuration: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 Potassium will lose 1 electron and become the potassium ion K +. Oxygen configuration: 1s 2 2s 2 2p 4 Oxygen will gain 2 electrons and become the oxide ion O 2-. Two potassiums are needed to combine with one oxygen. Diagram: [ K ] + [ O ] 2- [ K ] + or [ K ] 2 + [ O ] 2- Formula:K 2 O Name:Potassium oxide

12. Reaction between Aluminum and Bromine Student Practice Diagram the bonding between Al and Br, write the formula, and give the name. Describe how ions can be formed as a result of electron transfer.

13. Reaction between Aluminum and Bromine Diagram the bonding between Al and Br, write the formula, and give the name. Diagram: [Al] 3+ [ Br ] - 3 Formula: AlBr 3 Name: Aluminum bromide GO TO WHITE BOARD PRACTICE FOR IONS Describe how ions can be formed as a result of electron transfer.

14. Draw the transfer of electrons Draw the electron transfer between potassium and chorine. –Demonstrate on board here. Pass out ionic practice II Pass out polyatomic ion periodic table - And discuss Pass out Ionic Bonding HO

15. Metal + Nonmetal Ionic compounds are generally composed of a metal combined with a nonmetal(s) Pass Out Electronegativity Chart Ionic bonds have electronegativity differences greater than or equal to 1.8 Electronegativity Difference Table 16.4 (pg. 462) gives electronegativity differences and bond types Predict whether a compound of two elements would be ionic from the position of the elements in the periodic table or from their electronegativity values.

16. Ion Activities Review polyatomic handout Ion Practice Handout Ion cut and paste activity White Board Practice

17. Do not write – Science Standards Chap 16: Covalent Bonding Standard: PS2E: Compounds are composed of two or more elements bonded together in a fixed proportion by sharing electrons between atoms, forming Covalent bonds. Such compounds consist of well-defined molecules. Formulas of covalent compounds represent the types and number of atoms of each element in each molecule. Target: Describe the covalent bond as the electrostatic attraction between a pair of electrons and positively charged nuclei Describe how the covalent bond is formed as a result of sharing electrons. Predict whether a compound of two elements would be covalent from the position of the elements in the periodic table or from their electronegativity values. Compare and explain the properties of substances resulting from different types of bonding.

18. Describe the covalent bond as the electrostatic attraction between a pair of electrons and positively charged nuclei Covalent bonds occur between nonmetals since both want to gain electrons. They share electrons to achieve a stable configuration Electron Dot Diagrams Need 1 electron:HFClBrI Need 2 electrons:OSSeTe Need 3 electrons:NPAs Need 4 electrons:CSi GO to Types of Chemical bonds/covalent bond HO

19. Student Practice: Write the Lewis (electron dot) structures for each atom. Single covalent bonds Sharing 1 pair of electrons 1) H 2 2) HCl 3) CCl 4 GO to Covalent molecule practice (kits) Double covalent bonds Sharing 2 pair of electrons 4) O 2 Triple covalent bonds Sharing 3 pair of electrons 5) N 2

20. Review of Characteristics of Covalent Bond (polar and Nonpolar) Both: Combine NM + NM Both: Low melting points, usually gases and liquids, soft solids at room temp. Both: Do not conduct electricity Both: Consist of separate molecules Polar: Molecules have weak charges due to unequal attraction for electrons. ex. O-H, N-H, C-O, H-Cl, all soluble in water

21. Review of Characteristics of Covalent Bond (polar and Nonpolar) (Cont) Nonpolar: Molecules have slight to no charges due to equal attraction of electrons. Not soluble in water but soluble in organic solvents, ex. Alcohol or petroleum. Ex. C-C bond, C-C-C-C-C

22. Characteristics of Ionic Bonds Metal and nonmetal High melting points, usually a solid. Conducts electricity when melted or dissolved in water. Well defined crystals Usually soluble in water.

23. Student Practice Covalent Molecule Work Sheet Covalent Bonding Kits