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Bonding/Nomenclature. Review. How do ions form?. Cations Gain or lose? Ionization energy? Electron affinity? Anions Gain or lose? Ionization energy? Electron affinity?. Write chemical formulas. Criss-cross charges. Ionic compounds are neutral...the charges have evened out.
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Bonding/Nomenclature Review
How do ions form? • Cations • Gain or lose? • Ionization energy? • Electron affinity? • Anions • Gain or lose? • Ionization energy? • Electron affinity?
Write chemical formulas. • Criss-cross charges. • Ionic compounds are neutral...the charges have evened out. • Formula unit = empirical formula = simplest ratio of atoms
Name ionic compounds. • Name the cation. Is it a transition metal, Sn, or Pb? • Name the anion. Is it a polyatomic ion? • WATCH OUT FOR REDUCED FORMULAS! TRICKY!!! • Example: Pb(SO4)2, CuO, Cu2O
Properties of Ionic Compounds • Brittle • Dissociates in water • Conduct electricity when dissolved • Solid at room temperatures • HIGH melting points • Crystals (ionic crystal = unit cell)
Naming Covalent Compounds • Use prefixes! • No mono- on the first word. • Always end in -ide.
Writing Formulas for Covalent Compounds • Prefixes tell the subscripts. • NO CRISS-CROSSING NEEDED! 8-)
Drawing Lewis Structures • Total valence electrons • Pair the electrons • Set up the atoms and tie them together. • Place remaining pairs on terminal atoms and work toward the central. • Make sure every atom is satisfied.
Answering Questions about Lewis Structures • How many single bonds? • How many double bonds? • How many non-bonded electron pairs? • How many areas of electron density? • What is the VSEPR shape?
Properties of Covalent Compounds • Does not dissociate in water • Does not conduct electricity even when dissolved • Lower melting point • Not always solid at room temp • Not crystals...CALLED MOLECULES