1. Describe the trends found in the periodic table with respect to:

a) atom size

b) ionization energy

c) 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?A.iodine (I)B.fluorine (F)C.lithium (Li)D.rubidium (Rb)

Types of reactions and reactivity

•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

•Formation of binary compound from its elements

2 Mg(s) + O2(g) --> 2 MgO(s)

S8 (s) + 8 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)

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 + XDecomposition reactions take place only when energy is added.

a)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)

c) Decomposition of Metal Chlorates

* when heated, metal chlorates decompose into a metal chloride and oxygen

2 KClO3 (s) --> 2 KCl (s) + 3O2 (g)

*The equation represents an incomplete chemical reaction.

Al + Cl2 -->

What is the product of the chemical reaction?

* Al2Cl3

* AlCl

* AlCl2

* AlCl3

*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

•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 nonmetalsException: Hydrogen replaces metals and

metals can replace hydrogen

•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.

 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

•Examples:

1. Cu(s) + AgNO3(aq) -->

2. Cl2(g) + NaBr(aq) -->

3. Mg(s) + HCl(aq) -->

•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

•Examples:* KI (aq) + Pb(NO3)2 (aq) -->

* Mg(C2H3O2)2 (aq) + Na3PO4

(aq) -->

• 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

•Examples:

1. CH4 + O2 -->

2. C8H18 + O2 -->

3. C6H12O6 + O2 -->

*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?