1. Compounds and Molecules
4.1
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2. What are compounds?
Two or more elements chemically combined to form new substances.

3. What are compounds? Chemical Bonds
– the attractive forces that hold different atoms or ions together
Bonds distinguish compounds from mixtures.

4. Chemical Formula
C12H22O11 can only be sugar
H20 can only be water

5. Parts to the Formulas
2H2O
Subscript
Coefficient

6. Parts to the Formulas
Coefficient – gives the amount of molecules or moles
Subscript – tells the number of atoms or ions

7. Chemical Structure
Bond length
-the distance between two bonded atoms
Bond angle
-the angle formed between two bonded atoms

8. -atoms are represented balls, bonds are represented by sticks.
Models of compounds
Ball and stick model
-atoms are represented balls, bonds are represented by sticks. H H
Bond Angle O
Bond length

9. -chemical symbols represent the atoms.
Models of compounds
Structural formulas
-chemical symbols represent the atoms.
H H O

10. -show the space occupied by each atom represented in the compound.
Models of compounds
Space-filling
-show the space occupied by each atom represented in the compound.
Hydrogen
Oxygen

11. Structure of Compounds
Network Structures = strong solids
Molecules= weak solids, liquids, or gases

12. Ionic and Covalent Bonding
4.2
fun

13. Why Bond? Atoms bond so they can become stable!
They want to achieve a full outer energy level
They want 8 electrons.

14. 1. Ionic bond Na+ + Cl- NaCl
A bond formed by the attraction between oppositely charge ions.
The joining of a positive metal ion and a negative nonmetal ion
Na+ + Cl-
NaCl

17. Ionic bond NaCl Na+ + Cl- Formed by transferring electrons
Now each ion will have 8 valence electrons
NaCl
Na+ + Cl-

19. Ionic bond Properties They form network structures high melting points
Good conductors of electricity when dissolved or melted because of their ions

21. Metallic bond
Formed by the attraction between positively charged metal ions and the electrons around them.

22. Metallic bond Held together by free flowing electrons
Hold metallic elements together

25. Covalent Bonds Formed when atoms share one or more valence electrons
Formed between non-metals
May form single, double, or triple bonds

28. Covalent Properties They are poor conductors of electricity (no ions)
Low melting points.
form molecules

29. Polyatomic ion
An ion made of two or more atoms that are covalently bonded and that act like a single ion.
A molecule with a charge
Examples: carbonate (CO3)-2
Nitrate (NO3)-1

30. Fun

31. Compound Names and Formulas
4.3

32. REMEMBER!!!!!!!! If it starts with metal it is an ionic compound
If it starts with a nonmetal it is a covalent compound
If the formula contains a parentheses (polyatomic ion) it contains both ionic and covalent bonds
If it is just a metal it is metallic

33. Writing Ionic Formulas
Calcium Fluoride
Step Look up both positive and negative ions
Ca2+ F-1

34. Writing Ionic Compounds
Step 2
Criss-cross numbers down, making subscripts
Ca2+ F-1
Ca F2

35. Writing Ionic Compounds
Step 3
Combine your new compound.
Ca1 + F2  Ca1F2

36. Polyatomic ion
Aluminum Carbonate
Al (CO3)-2
Al2 (CO3)3
Al2(CO3)3

37. Naming Ionic Compounds
Step one – Name the first ion in the formula
Ex. CaCl2 – calcium
Na2(SO4) - sodium

38. Naming Ionic Compounds
Step two – Name the second ion
Ex. CaCl2 –Calcium Chloride
Na2(SO4)-sodium sulfate

39. PROBLEM Fe3+ O2- = Fe2O3 Fe2+ O2- = FeO
Ex. Fe2O3 and FeO are different compounds from different ions
Fe3+ O2- = Fe2O3
Fe2+ O2- = FeO

40. Solution-Roman Numerals
Same naming scheme
Add a Roman Numeral to identify the charge of the metal ion.

41. Solution-Roman Numerals
Fe2O3 = iron(III)Oxide
FeO = iron(II)Oxide
Remember!!!
R.N. is the charge, not the subscript of the metal.

42. Naming Covalent Compounds
Mono – 1
Di - 2
Tri - 3
Tetra - 4
Penta - 5
Hexa – 6
Hepta - 7
Octa - 8
Nona - 9
Deca - 10

43. Naming Covalent Compounds
Step 1
Identify the number of atoms in the first element
Ex. H2O two H atoms

44. Naming Covalent Compounds
Step 2
Identify the number of atoms in the 2nd element. Ex. H2O one O atom

45. Naming Covalent Compounds
Step 3
Name the compound with the appropriate prefixes. Ex. H2O
dihydrogen monoxygen

46. Naming Covalent Compounds
Step 4 add an -ide ending to the second element
Ex Dihydrogen monoxide

47. Empirical Formula The simplest chemical formula of a compound.
Different covalent compounds can have same empirical formula

49. Ch. 4.4