B F Ar Se Ba Si

1. B F Ar Se Ba Si Warm-upHow many valence electrons does each of the following atoms have? Draw a Bohr Diagram for each element

2. Chapter 8: Basic Concepts of Chemical Bonding • Why do TiCl4 and TiCl3 have different colors? ... different chemical properties? ... different physical states?

3. Chemical Bonding and Properties • Difference in colors is due to differences in electronic configuration for TiCl3 and TiCl4 • Differences in chemical behavior are due to differences in the types of bonds • Bond: forces that hold atoms together in molecules or ionic compounds.

4. Chemical Bonding • Types of bonds and types of substances • Ionic • Covalent • Metallic • The type of bond between atoms is partially responsible for the properties of the substance.

5. Why do atoms form bonds? Draw orbital diagrams for each of the following elements • Ne • Na • Cl • H • O

6. Notes handout

7. Octet Rule Lewis Dot Diagrams Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons. Used to illustrate an atoms valence electrons Used to illustrate how electrons rearrange during chemical reactions Why do atoms form bonds?

8. Lewis Symbols and the Octet Rule • Lewis Symbols:The number of valence electrons available for bonding are indicated by unpaired dots.

9. Lewis Symbols • These symbols are called Lewis symbols. • We generally place the electrons on four sides of a square around the element symbol.

10. Octet Rule Lewis Dot Diagrams Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons. Used to illustrate an atoms valence electrons Used to illustrate how electrons rearrange during chemical reactions Na Xe P Why do atoms form bonds?

11. Lewis Dot Practice • O • Te • Ca • Ba • Ne • I • Cs

12. Ions and Ionic Compounds • Ions are formed by adding or subtracting electrons from a neutral atom or molecule. • Cation: positive charge (remove electrons) Na+ • Anion: negative charge (add electrons) Cl- • Ions may be monatomic or polyatomic 03m07an1&2

13. Types of Ions • Monatomic ions • Single atom ions • O 2- • Na+ • Al3+ • Polyatomic ions • More than one atom ions • NH4+ • OH – • SO42-

14. Predicting Ionic Charges • Electron Counts of Stable Ions • Ions tend to have the same number of electrons as the nearest noble gas. • Main group ions of a given element tend to be different by two units of charge. • Transition metals are not as predictable, but +2 and +3 are common. ion_charges.exe

15. Main Group Elements Note periodicity of charges

16. Transition Elements • Not periodic; +2 and +3 common

17. Charges and Formulas of Oxoanions • Oxoanions generally have the same charge as the simple anion of the same nonmetal. Related to position in the periodic table; note exceptions for B, C, N Polyatomic Ions tend to reflect the charge of the base element

18. Practice on Ionic Charges • Pair Share: What is the common charge of an ion of potassium, K? • Pair Share: What is the common charge of an ion of sulfur, S? • Pair Share: What is the common charge of an ion of iron, Fe?

19. Ionic bond Example Lewis Dot diagram A positively charged ion is attracted to a negatively charged ion. A transfer of electrons Metal and a Non-Metal NaCl Why do atoms form bonds? Na Cl Na Cl

20. Practice Mg, S Ca, Br Metal Non-Metal Why do atoms form bonds?

21. What holds Ionic bonds together?

22. Formation of an Ionic Compound Vd02_007.mov

23. Properties of Ionic Bonds • Ionic bonds are very strong, so separating ions requires much energy • High melting points, boiling points • Crystals are hard and brittle • Electrical insulators when solid, electrical conductors when molten or dissolved in water • Demo: electric_pickle.mov

24. Electrical Conductivity Solid NaCl Liquid NaCl 03s11vd1

25. Structure and Properties • Why are crystalline solids brittle, whereas metallic solids are malleable?

26. Structure and Properties Brittleness brittle2.mov maleable2.mov

27. Examples of Ionic Formulas • What is the formula of each of these compounds?

28. Crisscross Method Example Ca and F Write the element symbols for the cation and anion, with the cation on the left and the anion on the right. Write each ion’s charge as a superscript. Crisscross the two charges moving them downward diagonally from one superscript to the other subscript. Writing Formulas for Ionic Compounds

29. Practice Li and O Mg and O Ca and N Writing Formulas for Ionic Compounds

30. Practice • Rewrite these incomplete formulas as correct formulas. AlS CaP BaBr • Make formulas from the following ions: Fe2+, PO43-Sc3+, O2-

31. Bonding with a partner • You will receive a card with an ion. • You will find another person with the opposite charge from you. • You will write the ions on your paper and the formula they will create together. • Exchange cards and repeat the steps again until you fill up your paper.

32. Ionic_Formula.exe Chemical Formulas • Remember • Combine ions to obtain electrical neutrality

33. Formula  Name Example: Li2O Name the cation Name the anion, changing the ending to ide Lithium Oxygen + ide Lithium Oxide Naming Binary Ionic Fixed Charge Compounds(Formula  Name)

34. Name  Formula Example: Calcium Chloride Ca +2 and Cl -1 CaCl2 Identify the ions involved List the cation first and then the anion Determine that charge of each ion involved Balance the charges so the compound is neutral. Naming Binary Ionic Compounds

35. Practice Write the structural formula for the following: Hint: separate them into ions and then criss cross Magnesium phosphide Calcium iodide Beryllium oxide

36. Formula  Name CoCl2 Example: Cobalt II chloride Name the cation Determine the charge of the anion Based on the anion, what charge does the cation need to make the compound neutral. Write the cation charge in parenthesis as a roman numeral Name the anion. Naming Binary Ionic Compounds STOCK (Transitional Metals)

37. Name  Formula Example: Calcium Chloride Copper(II) Oxide List the cation first and then the anion Give the cation the charge stated in the name Determine the charge of the anion Balance the charges so the compound is neutral. Ca +2 and Cl –1 CaCl2 Cu + 2 and O –2 CuO Naming Binary Ionic Compounds Stock (Name  Formula)

38. Practice • Writing Formulas “Transition Metals (stock Method)” wksheet

39. Naming Ternary Molecular Structures

40. Rally Table • NaF • K2CO3 • MgCl2 • Be(OH)2

41. Practice Worksheet

42. Brain Teaser • Write the formula for the following elements: Potassium and Phosphorus • Name the following compounds • SrS • Cu2S • Iron (II) oxide • Lithium cyanide

43. Compounds • How do we distinguish between ionic and covalent compounds? • What do you notice?

44. Covalent bond Shared pair of electrons between two atoms. Non-metal and Non-metal Why do atoms form bonds?

45. Lewis Structures • Lewis Structures A representation of a molecule that shows how the valence electrons are arranged among the atoms in the molecule * G. N. Lewis • Lewis Dot Examples

46. Molecule Diatomic Molecules Super 7 A group of atoms united by a covalent bond A few elements only exist as a pair of atoms never as a single lone atom Cl2, I2, F2, Br2, O2, H2, N2 Why do atoms form bonds?

47. Round Table – Covalent Bonding • SiH4 • NH41+ • H2Se • HCl • HF • *SO42-

48. Characteristics of covalent bonds Single Bonds Ex. H2 Double Bonds Ex. O2, H2CO Triple Bonds Ex. N2, C2H2 Can form multiple bonds satisfy the octet rule Two atoms share exactly one pair of electrons. Two pairs of electrons shared between two atoms. Three pairs of electrons are shared between atoms Why do atoms form bonds?

49. Properties of Covalent Bonds • Solids are usually soft • low melting points • low boiling points • Properties arise because molecules are not strongly held together • Usually found with nonmetals

50. Why do atoms form bonds? Specifies which atoms are bonded to each other Distinguish the difference between substances with the same molecular formula Structural Formulas