2: Bonds, James Bonds How can we apply the physical and chemical properties of elements to predict the formation of compounds?

Drill 1: 10.18 (A Day) 10.23 (B Day) 15 periwinkles = 5 snails 12 snails = 1 fish 300 fish = 1 shark How many sharks are in 2500 periwinkles? How many snails are in 3 sharks? Outcome: I can identify bond types based on chemical and physical properties.

CW 1: What Kind of Bond will Form? Describe the electronegativity difference and the type of element (metals or nonmetals) involved in each of the types of bonds. Bond Type Electronegativity Difference Types of Elements Involved Ionic   Polar Covalent Nonpolar Covalent Metallic Very Large, ≥ 2.0 Metal and Nonmetal Moderate, 0.4 to 2.0 Nonmetals Very small, 0.0 to 0.4 Nonmetals Not important! Metals

CW 1: What Kind of Bond will Form? difference in electronegativity 0.4 2.0 nonpolar covalent bond polar covalent bond ionic bond larger distribution of charge bonds become more “ionic like”

CW 1: What Kind of Bond will Form? Find and highlight Na and Cl in yellow. Find and highlight C and O in green. Which pair would form an ionic bond? Na (metal) and Cl (nonmetal) Which pair would form a covalent bond? C (nonmetal) and O (nonmetal) Considering the position of the elements you highlighted, which pair of elements would you expect to have a large electronegativity difference? Explain. The farther apart, the greater the electronegativity difference: the metal (Na) and the nonmetal (Cl).

CW 1: What Kind of Bond will Form? Element Electron Configuration # Valence Electrons Electronegativity Value (Page 7) Na 1s2 2s2 2p6 3s1 1 0.9 F 1s2 2s2 2p5 7 4.0 How many valence electrons are needed for a stable electron configuration? A full octet: 8 valence electrons Fluorine has 7 valence electrons. How does this explain the very high electronegativity value of fluorine? It is close to a full octet, wants to gain an electron, not lose any.

CW 1: What Kind of Bond will Form? Element Electron Configuration # Valence Electrons Electronegativity Value (Page 7) Na 1s2 2s2 2p6 3s1 1 0.9 F 1s2 2s2 2p5 7 4.0 How many valence electrons would sodium have if it lost its 3s1 electron, forming the cation Na+1? Is this configuration more stable, or less stable? If the 3s1 e- were lost, the highest energy level would be 2, which has a full octet, making it more stable. Why does sodium have such a low electronegativity value? Losing the 3s1 e- will make the atom more stable, so the atom wants to lose it.

CW 2: Ionic, Metallic, or Covalent Virtual Lab Go to SRHSchem/ unit 2 to access the virtual lab. In the table, you should summarize and explain each property. Your goal is to understand, not memorize. This is on the quarterly assessment.

Summary 1: 10.18 (A Day) 10.23 (B Day) HW 1: Intermolecular Forces Notes Complete CW 1 and CW 2. Outcome: I can identify bond types based on chemical and physical properties.