1. Warm up: Answer 1-3 on Ch. 8.4 Notes
Describe the trends found in the periodic table with respect to:
atom size
ionization energy
Electronegativity

2. Which pair of arrows correctly represents how atomic radii change, from smallest radius to largest radius, on the periodic table of the elements?
A B.
C D.

3. Which of these elements has the highest electronegativity?
iodine (I)
fluorine (F)
lithium (Li)
rubidium (Rb)

4. Types of reactions and reactivity
Ch. 8.4 to 8.5
Types of reactions and reactivity

5. A + X --> AX Ch. 8.4 Composition rxns
In a composition reaction, also known as a synthesis reaction, two or more reactants combine to form a single product.
This type of reaction is represented by the following general equation.
A + X --> AX

6. Composition cont. 2 Mg(s) + O2(g) --> 2 MgO(s)
Formation of binary compound from its elements
2 Mg(s) + O2(g) --> 2 MgO(s)
S8 (s) O2(g) --> 8 SO2(g)
2 Na(s) + Cl2(g) --> 2 NaCl(s)
Reactants can also be compounds.
CaO(s) + H2O(l) --> Ca(OH)2(s)
SO2(g) + H2O(l) --> H2SO3(aq)
CaO(s) + SO2(g) --> CaSO3(s)

7. Decomposition Reactions
In a decomposition reaction, a single reactant undergoes a reaction that produces two or more simpler substances.
Decomposition reactions are the opposite of composition reactions.
They are represented by the following general equation.
AX --> A + X
Decomposition reactions take place only when energy is added.

8. Types of Decomposition RXNs
Decomposition of Binary Compounds
compound breaks up into its elements
2 H2O (l) --> 2 H2 (g) + O2 (g)
2 HgO (s) --> 2 Hg (l) + O2 (g)
Decomposition of Metal Carbonates
when heated, metal carbonates decompose into a metal oxide and carbon dioxide
CuCO3 (s) --> CuO (s) + CO2 (g)

9. Types of decomp. cont
c) Decomposition of Metal Chlorates
when heated, metal chlorates decompose into a metal chloride and oxygen
2 KClO3 (s) --> 2 KCl (s) + 3O2 (g)

10. Practice The equation represents an incomplete chemical reaction.
Al + Cl2 -->
What is the product of the chemical reaction?
Al2Cl3
AlCl
AlCl2
AlCl3

11. Independent Practice
The chemical equation represents the reaction between sodium (Na) and oxygen (O2).
4 Na + O2 -->
What is the product of this reaction?
2 Na2O
2 NaO
2 NaO2
2 Na2O2

12. Ch. 8.5 Single Replacement RXNs
In a single replacement reaction, one element replaces a “similar” element in a compound.
Single replacement reactions can be represented by the following general equation:
Element + Compound --> Element + Compound
A + BC --> B + AC
“Similar” = metals replace metals
= nonmetals replace nonmetals
Exception: Hydrogen replaces metals and
metals can replace hydrogen

13. Activity series
Activity series is a list of elements organized according to the ease with which the elements undergo certain chemical reactions.
For metals, greater activity means a greater ease of lose of electrons (forming cations).
For nonmetals, it means a greater ease of gaining electrons (making anions).
Use the provided list to determine if any given SDR will occur.

14. reacts with water and acids reacts with acids replacing hydrogen
 Metals
Name Symbol
Lithium Li+
Sodium Na+
Potassium K+
Rubidium Rb+
Barium Ba+2
Strontium Sr+2
Calcium Ca+2
Decreasing activity ↓
reacts with water and acids
Magnesium Mg+2
Aluminum Al+3
Manganese Mn
Zinc Zn+2
Chromium Cr+3
Iron Fe
Cadmium Cd+2
Cobalt Co+2
Nickel Ni+2
Tin Sn
Lead Pb
reacts with acids replacing hydrogen
Hydrogen H2
Antimony Sb
Bismuth Bi
Copper Cu
Mercury Hg
Silver Ag+1
Platinum Pt
Gold Au
fairly unreactive
Activity series
Non-metals
Fluorine F2
Chlorine Cl2
Bromine Br2
Iodine I2

15. Examples: SDR Cu(s) + AgNO3(aq) --> Cl2(g) + NaBr(aq) -->
Mg(s) + HCl(aq) -->

16. Double Replacement Reactions
In double-replacement reactions, the positive ions of two compounds exchange places to form two new compounds.
Double replacement reactions can be represented by the following general equation:
AX BY --> AY BX

17. Double Replacement Reactions
Examples:
KI (aq) + Pb(NO3)2 (aq) -->
Mg(C2H3O2)2 (aq) + Na3PO4 (aq) -->

18. Combustion Reactions
In a combustion reaction, a substance combines with oxygen (O2), releasing a large amount of energy in the form of light and heat.
Most combustion reactions involve the reaction of a carbon-based compound with oxygen. The products are carbon dioxide and water.
They are represented by the following general equation.
X + O2 --> CO2 + H2O

19. Combustion Examples: CH4 + O2 --> C8H18 + O2 -->
C6H12O6 + O2 -->

20. Reflection
You have one minute to answer these two questions concerning today’s lesson.
What was the most important thing you learned?
What is one question you would still like answered? 20