Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two or more nonmetals. Metallic bonds occur between metal atoms only.

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3 Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two or more nonmetals. Metallic bonds occur between metal atoms only.

4 Using chemical equations to show ionization: Na Na + + e - Al Al e - Ag Ag + + e -

5 Using chemical equations to show the formation of negative ions: Cl + e - Cl - O + 2e - O 2- P + 3e - P 3-

6 Write the name and symbol of the ion formed when a. a sulfur atom gains two electrons b. a calcium atom loses two electrons c. a zinc atom loses two electrons d. a fluorine atom gains one electron Sulfide ion S 2- Calcium ion Ca 2+ Zinc ion Zn 2+ Fluoride ion F -

7 How many electrons are lost or gained in forming each ion? a. Ba 2+ b. As 3- c. Cu 2+ a. 2 electrons are lost. b. 3 electrons are gained. c. 2 electrons are lost.

8 How many electrons will each element gain or lose in forming an ion? a. calcium a. 2 lost b. bromine b. 1 gained c. aluminum c. 3 lost d. nitrogen d. 3 gained e. strontium e. 2 lost f. iodine f. 1 gained

9 Transition Metal Ions Some transition metals have only 1 charge. Examples: Ag +, Ni 2+, Zn 2+, Cd 2+ Some transition metals can form cations of various charges. Examples: Cu + and Cu 2+, Fe 2+ and Fe 3+ See list on page 255.

10 Formation of Ionic Compounds The cations and anions are bonded together by electrostatic forces called Ionic Bonds Ionic compounds are electrically neutral. Formula unit is the lowest whole-number ratio of ions in an ionic compound. Formula unit is to ionic compound as molecule is to molecular (covalent) compound.

11 NaCl is the chemical formula for sodium chloride.

12 Lewis Structures for Ionic Compounds Draw Lewis structures for the following: a.) potassium reacting with iodine b.) aluminum reacting with oxygen c.) calcium reacting with chlorine d.) magnesium reacting with fluorine e.) aluminum reacting with sulfur

13 Properties of Ionic Compounds 1. Most ionic compounds are crystalline solids at room temperature. 2. Ionic compounds generally have high melting points.

14 3. Ionic compounds can conduct an electric current when melted or dissolved in water.

15 Coordination Number The coordination number of an ion is the number of ions of opposite charge that surround the ion in a crystal. In NaCl, each ion has a coordination number of 6.

16 In CsCl each ion has a coordination number of 8. In TiO 2, each Ti 4+ ion has a coordination number of 6. Each O 2- ion has a coordination number of 3.

17 Use Lewis structures to help you write the correct chemical formula for the compounds formed from each pair elements. a.) K and S b.) Ca and O c.) Na and O d.) Al and N a. K 2 S b. CaO c. Na 2 O d. AlN

18 Use Lewis structures to help you write formulas for each compound. a.) barium chloride b.) magnesium oxide c.) lithium oxide d.) calcium fluoride a. BaCl 2 b. MgO c. Li 2 O d. CaF 2

19 Which pairs of elements are likely to form ionic compounds? a.) Cl, Br b.) Li, Cl c.) K, He d.) I, Na b. Li, Cl d. I, Na

20 Bonding in Metals

21 Metallic Bonds Metallic bonds consist of the attraction of the free-floating valence electrons for the positively charged metal ions. Ductile the ability to be drawn through a die and made into wire.

22 Malleable the ability to hammer metals into sheets and/or force them into shapes. Ionic solids are not malleable, they will shatter when hammered due to the repulsion between ions of the same charge.

23 Conductivity the sea of electrons available in metals allow them to be good conductors. Electrons are able to flow in and out of a metal because the valence electrons are not fixed (delocalized electrons).

24 Crystalline Structure of Metals Metal atoms are arranged in very compact and orderly patterns. The 3 arrangements for the atoms are known as the closest packed arrangements.

25 Alloys Alloys are mixtures composed of two or more elements, at least one of which is a metal. The properties of alloys are superior to the properties of their constituent elements.

26 Substitutional alloys are made of atoms that are similar in size. One kind of atom is replacing another kind of atom in the crystal. Interstitial alloys are made of atoms of different sizes. The smaller atoms can fit into the interstices between the larger atoms.

27 State the number of electrons either lost or gained in forming each ion. a. Br - a. Gained 1 electron b. Na + b. Lost 1 electron c. As 3- c. Gained 3 electrons d. Ca 2+ d. Lost 2 electrons e. Cu + e. Lost 1 electron f. H - f. Gained 1 electron

28 How many electrons must each atom lose to attain a noble-gas electron configuration? a.ca b.al c.li d.ba a.2 b.3 c.1 d.2

29 Why do nonmetals tend to form anions when they react to form compounds? Most nonmetals gain 1, 2, or 3 electrons to achieve a noblegas electron configuration.

30 How many electrons must be gained by each of the following atoms to achieve a stable electron configuration? a. N b. S c. Cl d. P a.3 b.2 c.1 d.3

31 Which of the following pairs of atoms would you expect to combine chemically to form an ionic compound? a. Li and S a. Yes b. O and S b.no c. Al and O c. Yes d. F and Cl d.no e. I and K e. Yes f. H and N f. No

32 Which of the following pairs of elements will NOT form ionic compounds? a.sulfur and oxygen b.sodium and calcium c.sodium and sulfur d.oxygen and chlorine a, b, and d

33 Explain why molten MgCl 2 does conduct an electric current although crystalline MgCl 2 does not. Ions are free to move in molten MgCl 2, but not in crystalline MgCl 2.

34 Explain why metals are good conductors of electricity. They have many mobile valence electrons. Electrons in the current replace electrons leaving the metal.