1. Bonding and Chemical Reactions
Chapters 6 and 7

2. Compounds and Molecules
Chemical structure: the arrangement of atoms in a substance
Chemical Bond: forces that hold atoms together in a compound

3. Bond Models bond length: models distance between nucleus of 2 atoms
bond angle: models angle the bonds between 3 or more atoms form
space-filling: shows space that atoms take up
bond angle
space-filling

4. Nature of Bonds Some bonds are stronger than others, but all
bonds can:
bend
stretch
rotate without breaking

5. Chemical Structure and Properties
compounds with networks are strong solids
ex: diamond, quartz, many rocks
networked compounds have melting and boiling points
ex: salts, rocks, diamonds

6. Chemical Structure and Properties (cont’d)
Some compounds are made of bonded ions
ex. NaCl (strong attraction between ions)
Some compounds are made of molecules
ex: H2, O2, N2, CO2 (gases with weak attraction for each other)
Hydrogen bonds are very strong

7. Bonding Atoms bond to gain 8 valence electrons-
stable electronic configuration
2 basic types of bonding:
-ionic
-covalent

8. Ionic Bonding Ionic Bonds: between oppositely charged atoms;
usually on opposite sides of the periodic table
(metal and nonmetal)
transfer electrons
form networks, not molecules
conduct electricity when dissolved
Lithium
Flourine

9. Covalent Bonds Covalent Bonds: share electrons; usually between
2 elements close on the periodic table (nonmetals)
nonpolar covalent bond: e- shared equally
polar covalent bond: e- shared unequally

10. Metallic Bonding
“sea of electrons”: electrons can “float” freely between atoms; allows metals to conduct electricity well

11. Polyatomic Ions Compounds with both ionic and covalent bonds
acts as a single unit (like ions)
parentheses group polyatomic ion in a
compound
most names end in “ite” or “ate” (depending on # of oxygen atoms)

12. Compound Names and Formulas
(Compounds have specific names so you can
tell how many and what atoms are in the
compound/moleule)

13. Ionic Naming Cations: the name of the element
Anions: have “ide” at the end of the element’s name
Ionic compounds must have a total charge of
zero
Sodium Chloride
Cation is ALWAYS FIRST
Anion is ALWAYS LAST
Na+1 + Cl-1 = NaCl (0 charge)

15. Transition Metal Naming
Transition metals show their charges as Roman numerals because they can change charge
FeO = Fe+2 + O-2
Iron (II) Oxide
Fe2O3 = Fe+3 + O-2
Iron (III) Oxide

16. What is the formula for Lithium oxide
What is the formula for Lithium oxide? Li- ____ O- ____ formula: _______________________

17. What is the name for CuCl2
What is the name for CuCl2? cation- ___________ anion- ___________, ending- __________ name- _____________________________

18. Covalent Naming
To name covalent compounds, put a numerical prefix in front of the element’s name:
1- mono hexa
2- di hepta
3- tri octa
4- tetra nona
5- penta deca
If only 1 cation is present, no prefix is needed
Atom to the right of the first cation ends in “ide”

19. What is the name of H2O? _______________________

20. Formulas
Empirical Formula: smallest whole-number ratio of atoms in a compound
Molecular Formula: how many atoms are in a molecule of a compound
GLUCOSE
Molecular Formula
Empirical Formula
C6H12O6
CH2O

21. Organic and Biochemical Compounds
Organic compound: covalently bonded compound that contains carbon
Polymer: large molecule formed by more than 5 monomers (small units)
ex. DNA

22. Chemical Reactions Result in rearranged atoms
Involve changes in energy
Exothermic: release energy (heat, fire, fizz, etc)
Endothermic: absorb energy (drop in temp.)
-remember, chemical energy is stored in chemical bonds

23. Endothermic Reaction
Exothermic Reaction

24. Chemical Equations Describing Coefficients: individual atom = “atom”
2Mg  2 atoms of magnesium
covalent substance = “molecule”
3CO2  3 molecules of carbon dioxide
ionic substance = “unit”
4MgO  4 units of magnesium oxide

25. Chemical Equations (cont’d)

26. Coefficient  subscript = # atoms
Balancing Steps
1. Write the unbalanced equation.
2. Count atoms on each side.
3. Add coefficients to make #s equal.
Coefficient  subscript = # atoms
4. Reduce coefficients to lowest possible ratio, if necessary.
5. Double check atom balance!!!

27. Balancing Example Al + CuCl2  Cu + AlCl3 Al Cu Cl 3 2 2 3 2 2 3 3 2
Aluminum and copper(II) chloride form copper and aluminum chloride.
Al CuCl2  Cu AlCl3 Al Cu Cl
2 
 2
3 
6   6
 3

28. Chemical Equations ___ CH4 + ___ O2 ___ CO2 + ___ H2O
methane and oxygen yield carbon dioxide and water
___ CH4 + ___ O ___ CO2 + ___ H2O
Reactants
Products

29. Balance the Reaction.
___ Mg + ___ O ___MgO

30. Balance the reaction.
___ H2O ___H2O + ___ O2

31. Reaction Types Synthesis: combines substances A + B AB
Decomposition: substances are broken apart
AB A
Combustion: ALWAYS has O₂ as a reactant
AB + O₂ AO + BO

32. Reaction Types Single-Replacement (single-displacement):
one element takes the place of another
AX + B A + BX
Double-Replacement (double-displacement):
two compounds appear to exchange ions
AX + BY AY + BX