1. Chemical Bonding
Chemical bond – The attractive force between the protons of one atom for the electrons of another atom
Determined by electronegativity
Chemical energy – a type of stored (potential) energy that is involved in the formation and breaking of chemical bonds.
When bonds break... energy is absorbed!
CuSO4·5H2O + energy → CuSO H2O ↑
breaking this bond by adding energy!

2. Bonding When bonds form... energy is released! Mg + O → MgO + Energy
Bonding & Energy
When bonds form, energy is released. Systems are more stable when they are at lower energy levels.
Therefore, atoms become more
stable when they form bonds
due to the release of energy.

3. Bonding Why do atoms bond? What group of elements do not bond?
to become more stable
to fill their valence shell(highest principal energy level)
It takes eight electrons to fill the valence shell, except for elements that only need two.
What group of elements do not bond?
Noble Gases
their outer shell is already completely filled.
The Octet Rule- Atoms bond in order to have eight electrons in their valence shells(or sometimes two), giving them the same electronic configuration as a noble gas.
Noble gases are stable. All elements want to be like the noble gases.

4. Bonding
Ionic Bond – the bond that forms between metal and nonmetal. Electrons are transferred from the metal to the non-metal.
The bond between cation and anion is very strong.
Determines physical and chemical properties of ionic substances
Ionic Substances
Called "Salts"
solids form a crystalline shape called a “lattice”
High melting points (solid at room temp.)
brittle
solubility – ability to be dissolved.
Ionic compounds dissolve in water
aqueous – dissolved in water
Salts do not conduct electricity as solids
Do conduct when melted(liquid) or aqueous
electricity is a flow of charged particles
Ions(charged atoms) move freely when liquid or aqueous

5. Ionic Compounds - Oxidation state : the charge of the ion.
Metals lose electrons and become positive
Nonmetals gain electrons and become negative
The number of electrons lost or gained determines oxidation state
Ex: Ca is in Group 2, has 2 valence electrons
becomes Ca2+
Therefore, its oxidation state = 2+
Ex: N is in Group 15, has 5 valence electrons
becomes N3-
Oxidation state = 3-
Several metals have more than one oxidation state
Many are transition metals
Example:
Copper can have one valence electron:
Copper can also have 2 valence electrons:
Cu+
Cu2+

6. Xe Lewis-Dot Diagrams Lewis-Dot diagrams
aka electron-dot diagrams or Lewis-Dot Structures
Shows valence electrons for atoms
Maximum number of valence electrons = 8 (think Octet Rule)
Valence electrons are drawn around the outside of the element symbol
The first 4 electrons are filled one to each side(top, right, bottom, left)
The next 4 electrons pair up with the first 4 after that
Example: Xenon is a noble gas, it has 8 valence electrons. Xe

7. Lewis-Dot Diagrams & Bonding
Can assist in determining how elements bond
Metals lose electrons
Nonmetals gain electrons
Dot diagrams show where and how many electrons are being transferred
1. Determine the number of valence electrons for each element and draw them in
2. Transfer electrons from the metal to the nonmetal
3. Determine if more than one ion is needed to fill the valence shell
4. Write the metal first with its oxidation state
5. Write the non-metal second with a full outer shell and brackets
6. Add coefficients if more than one atom was used O Na Na 2
Na+
[ O ]2-

8. Chemical Formulas
Chemical formula- expression indicating the elements in the compound and how many in the smallest unit of a substance
“Which atoms & how many”
Subscripts indicate how many but 1s are not written
Ex. NaCl 
Ex. Fe2O3 
Oxidation states can be determined from formulas
Chemical formulas are neutral
Anion & cation charges must total to 0
Start with the ion you know for sure
Example: NaCl  Na is Group 1 & always forms a 1+ ion. Therefore, Cl must be 1- to balance it.
Example: Fe2O3
· Fe is a transition metal, oxidation state is unknown
· O is Group 16 & always forms 2- ion, and there are 3
· Fe must be a 3+ in order to balance the negative charges of O
one Na atom and one Cl atom
two Fe atoms and three O atoms

9. IUPAC Naming System
Binary Compound – two different elements chemically combined
Two parts: Cation (metal) & Anion (nonmetal)
Ternary compounds – compounds with more than two elements.
Polyatomic ion replaces an anion(or cation)
Polyatomic ions – ions made from more than one element
Often made from multiple nonmetals
Most end in “-ate” or “-ite”
List on Page 7 of NC Reference Tables
IUPAC - International Union of Pure and Applied Chemists
These guys made the naming system
Cation is written first. Ending does not change
Anion is written second.
If it’s a nonmetal, ending is changed to “-ide”
If a polyatomic ion, ending is not changed
Certain Transition metals need a roman numeral
“Ti through Cu, Au, Hg, Sn & Pb”
Examples:
Sodium & chlorine
Calcium & Oxygen
Magnesium and sulfate
Iron (II) and bromine
Sodium chloride
Calcium oxide
Magnesium sulfate
Iron (II) bromide

10. Chemical Naming & Chemical Formulas
Determining a name from a formula
Same rules for naming; Cation first, anion second, roman numerals for transition metals
The amount indicated by subscripts doesn’t factor into the chemical name for ionic compounds
Example: MgBr2
Li2SO4
CuO
Determine a formula from a chemical name
Write the symbols for the cation & anion
Look up the charges. Roman numerals indicate the charge on transition metal
Calculate the amount of each ion and fill in subscripts
Magnesium bromide
Lithium sulfate
Copper (II) oxide

11. Metallic Bonds Positive metal ions surrounded by valence electrons
Valence electrons are held loosely, flow freely between ions
“positive ions in a sea of mobile electrons”
The bond is a result of the attraction between the positive ions and the mobile electrons.
The delocalized valence electrons give metals their properties
Luster, Malleability, Ductility, ability to conduct heat and electricity in the solid state.