1. What is a Chemical Bond?
The chemical attraction between elements which holds 2 or more atoms together with a chemical force

2. What is a Chemical Bond?
The bond is determined by the electron arrangement in the outer level or valence level
Oxidation tells how many electrons an element will gain, lose, or share and it is based on the valence number

3. What is a Chemical Bond?
A stable arrangement has 2 or 8 electrons in the outer level. (Ex. Helium - 2, Xenon - 8)
Called - the Octet Rule
All atoms desire to have 8 electrons in their outer shell (except Hydrogen and Helium who want 2)

4. Types of Bonds: Covalent Bonds
Occur when two atoms share electrons between outer energy levels
When elements in the 13, 14, & 15 (3,4 and 5) families bond with each other
When any element bonds to hydrogen

5. Types of Bonds – covalent (cont)
Properties:
can be broken easily
have low melting points
strong odors
change states easily
occur when an element bonds with itself ex.O2. called a diatomic bond

6. Covalent bond H + O H2O
Electrons are shared

7. Types of Bonds -Ionic Bonds
When a metal transfers an electron to a nonmetal
A metal becomes positively charged
more protons than electrons
A nonmetal becomes negatively charged
more electrons than protons
Families 1,2, 16, & 17 bond ionically and the Transition Metals (3-12)

8. Types of Bonds - Ionic Bonds (cont)
Properties:
Conduct electricity
Very strong bonds due to electrical attraction
Ions are arranged in regular repeating pattern called a crystal lattice:

9. Ionic Bond Na + Cl NaCl
Electron is transferred

10. Formulas and Equations
Formulas are used to represent a chemical reaction in the form of an equation
is an equal sign – called yield
The elements and compounds on the left of the
are called the reactants
The elements and compounds on the right of the are called the products

11. Formulas and Equations - cont
Subscript tells number of atoms of an element (Ex. H2O – the 2 tells you that there are 2 H atoms)
Coefficients tell how many molecules are present (Ex. 3H2O – the 3 tells you that there are 3 water molecules with 2 H and 1 O each for a total of 6 H and 3 O)

12. Formula Writing Rules Find the oxidation number
Put the oxidation numbers as superscripts above each element
Cross the oxidation numbers, drop the signs and write the numbers as subscripts
If it is multiple atoms in ( ) it is called a polyatomic ion. (CO3)2- Make no changes inside the ( ). Apply the same rules to it as a whole.

13. Na1+ O2- Parts of a formula There is a 2:1 ratio for Na:O Superscript
Na2O Na2O
Superscript
There is a 2:1 ratio for Na:O
No number means 1
Subscript
Coefficient

14. Formula Writing - cont
Most transition elements have so many electrons they are polyvalent. You can’t look at the periodic table to determine which oxidation number to use, so it will be given to you.
Example – Fe2+ Ferrous/Iron II or Fe3+ Ferric/Iron III

15. Naming Rules for Binary Ionic Compounds
If there are only 2 elements
Keep the metal name
Take the nonmetal (second element) drop the last syllable (the ending) and add ide
NaCl – Sodium Chloride
If the second part of the compound is a polyatomic ion, make no changes and write the words as written.
Ca(CO3) – Calcium Carbonate

16. Naming Rules for Binary Covalent Compounds
If there is only one atom just use the name with no prefix for the first element
If there is more than one atom use the prefix that indicates the number (di, tri, etc.)
For the second element use a prefix (mono, di, tri, etc.) drop the final syllable and add ide
CO2 – Carbon Dioxide
N2O – Dinitrogen Monoxide

17. Equations 2H2 + O2 -----> 2H2O
It takes lots of energy to bond chemically so elements must use their energy efficiently.
A chemical equation tells the story of a chemical reaction
Reactants are starting substances.
Products are the new substances.

18. Equations
The large numbers in front of some of the formulas are called Coefficients
These numbers are used to balance the equation because chemical reactions must obey the Law of Conservation of Matter
The number of atoms of each element on both sides of the equation must be the same because matter cannot be created nor destroyed.

19. Balancing Act
When balancing the equations, the only numbers that can be changed are the COEFFICIENTS.
Remember that subscripts must never be changed in order to balance and equation.

20. Law of Conservation of Matter
States that matter is not CREATED or destroyed, it only changes FORMS.
In a chemical reaction this means that all the atoms present at the START of the reaction are present at the end.

21. Law of Conservation of Matter
In a OPEN system, matter can enter from or escape to the surroundings.
Open beaker, flask, test tube, outside
In a CLOSED system, matter is not allowed to enter or leave.
Ziplock bag, balloon over a test tube, cap on a bottle.

22. Types of Reactions
In a chemical reaction, atoms are rearranged & changed in specific ways.
Synthesis- 2 or more simple substances combine to form one more complex substance
Fe + O2 FeO2 (rust)
HINT: only one product on right side of arrow

23. Synthesis

24. Types of Reactions
Decomposition occurs when one complex reactant breaks down into simpler products.
Examples:
H2O2----> H O 2
KClO3-----> KCl + O3
HINT: only 1 reactant on left side of arrow

25. Decomposition

26. Types of Reactions
Single Displacement- one element reacts with a compound and the element becomes a part of a compound.
Al+ CuCl > Cu + AlCl3
HINT: element + compound  new element + new compound

27. Single Displacement

28. Types of Reactions Double Displacement-
2 compounds react and form 2 NEW compounds
NaCl + HOH----> HCl + NaOH
HINT: compound + compound  new compound + new compound

29. Double Displacement

30. Law of Conservation of Energy
Energy can neither be created nor destroyed. It can only change forms.
If energy is lost or released it is called EXOTHERMIC. The energy is Exiting the reaction
examples: combustion and burning
If energy is absorbed, it is called ENDOTHERMIC. The temperature decreases
examples: yeast in dough absorbs heat and air expands causing it to rise.

31. Reaction Rates
A rate describes how quickly reactants change to products.
Collision theory states that for molecules to react they must collide at proper angles.

32. Reaction Rates The rate is effected by 4 factors: 1) Temperature
2) Concentration
3) Surface Area- grind up or make particles smaller
4) Catalyst speed up the reaction & do not effect the products while Inhibitors slow down the reaction. Ex. food preservatives