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Catalyst: Complete the Chart. Hint: According to the octet rule, atoms lose or gain electrons, forming ions, in order to get a full outer shell with 8 electrons. If the atom loses electrons it is a positive cation and if it gains electrons it is a negative anion. Catalyst: Answers.
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Catalyst: Complete the Chart Hint: According to the octet rule, atoms lose or gain electrons, forming ions, in order to get a full outer shell with 8 electrons. If the atom loses electrons it is a positive cation and if it gains electrons it is a negative anion.
Catalyst: Answers Hint: According to the octet rule, atoms lose or gain electrons, forming ions, in order to get a full outer shell with 8 electrons. If the atom loses electrons it is a positive cation and if it gains electrons it is a negative anion.
TODAY’S OBJECTIVE:BONDING!!!!SWBAT Differentiate between IONIC &COVALENT BONDS A.K.A.: Why don’t you blow up when you eat sodium chloride since sodium is a highly reactive metal and chlorine is an extremely poisonous gas??
Agenda • Catalyst/HW Check (10) HW Review (10) Part 1: Ionic Compound Formula Review: Kris-Kross Method (20) PART 2: Ionic vs. Covalent Compounds • Ionic vs. Covalent Notes (20) • Ionic vs. Covalent Lab (40) • Ionic vs. Covalent Conductivity Demo (10) • Closing (5)
Homework Answers • Having equal amounts of positive and negative charge is called electroneutrality. • An electrically charged group of two or more bonded atoms that functions as a single ion is a polyatomic ion. • Collections of cations are never found without a similar number of anions (or sometimes electrons) nearby to effectively neutralize the charges. • The names for cations come from the element from which they are formed. • When an element forms two or more positive ions, the ions are distinguished by using roman numerals to indicate the charge. • The name of a simple anion is formed by changing the ending of the element name to –ide. • A subscript is a whole number written below and to the right of an element’s symbol, and it is used to denote the number of atoms in a formula. • Any chemical compound that is composed of oppositely charged ions is called an ionic compound.
More HW Answers • K+ + Br- → KBr • Ba2+ + F- → BaF2 (2 F- to balance 2+ charge) • Sn4+ + O2- → SnO2 (2 O2- to balance 4+) • Cs2+ + Br- → CsBr2 (2 Br- to balance 2+) The rest of the problems are coming up as practice…
Ca2+As3- Kris Kross Method! Ca3As2
Just kris kross the positive and the negative charges Na1+Cl1- NaCl Pb4+O2- Pb2O4
Practice Problems • What ionic compound is formed? • Cobalt (II) and Bromine • Mercury(I) and Sulfur • Aluminum and Iodine Hints: • Periodic table groups tell us how many valence electrons • Draw Lewis structure • Metals lose electrons to form positive cations • Nonmetals gain electrons to form negative anions • Compounds must be neutral (equal # of + and – charges)
Part 2! Ionic vs. Covalent Bonds • Make a Chart in your notes that looks like this:
Ionic vs. Covalent Bonds • Bond Strength = the energy needed to break the bonds between atoms in a compound.
Ionic vs. Covalent Bonds Water (H2O) molecules Lithium Chloride (LiCl) crystal lattice
Investigation: Ionic vs. Covalent • You will work in groups of 4. (2 groups per table) • Lab WS is due at end of class • Safety! Do not put any test substances near your eyes or mouth. • Clean Up: Pour liquids down the sink and solids in the trash. • Objective: Conduct four tests on four substances. Predict whether they are ionic or covalent. • Ms. Boon will run the conductivity test.
Exit Slip • What is the formula for a compound between: Ca & F? • Compare at least one difference between ionic & covalent compounds? • Does the compound MgBr2 share electrons or transfer them between the atoms?
Practice- Ionic or covalent? • SH6 • KCl • H3C3O2 • N2 • CsBr • HF • CaCl2 • H2 • MgCl2 • NH3 • Li2S • Cl2 • H2O • Na3P • BaS