1. Chemical Bonding Review All atoms have valence electrons
Valence electrons- the electrons in the outermost energy level
Atoms that give up electrons become positive and are called cations
Atoms that gain electrons become negative and are called anions
Atoms with the same number of valence electrons have similar chemical properties

2. Chemical Bonding All the elements want to be like the Noble gases.
They’re chemically stable
They have a full outer shell
How do atoms go from being unstable to stable?
Elements will form bonds with other elements in order to become stable
A chemical bond is formed when two substances are more stable when bonded than they were before the bond.
When a bond is formed, energy is released!
Magnesium Demonstration:
Mg + O → MgO + light & heat

3. Bonding When bonds break... energy is absorbed!
CuSO4 · 5H2O + energy → CuSO H2O ↑
This bond is broken by adding energy!
Chemical energy is the energy involved that is either produced or absorbed when forming or breaking chemical bonds.

4. Chemical Bonding
Atoms gain stability by releasing energy. The more energy released, the greater the stability.
Therefore, atoms become more stable when they form bonds due to the release of energy.
Energy Released
Stability

5. Bonding
Atoms bond in order to be like the Noble Gases
They follow 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 do not bond
Their outer shell is already completely filled.
Metals will lose valence electrons so that their (full) inner shell becomes their valence shell
Nonmetals will gain electrons to fill their outer shell.
The type of bond is determined by each elements’ electronegativity.
Elements with a large difference in electronegativities will form ionic bonds (metals & nonmetals)
Nonmetals with similar electronegativities will form covalent bonds

6. Ionic Bonding
Ionic Bond– the bond that forms between metal and nonmetal
Electrons are transferred from the metal to the nonmetal.
The bond between cation and anion is very strong.
Determines chemical & physical properties of ionic compounds
Ionic Compound – Any substance formed from the bond between cation and anion. Also called a salt.
Physical Properties of ionic compounds
high melting points due to strong bond between cation & ion
Crystalline shape called lattice
Brittle
soluble – can be dissolved in water. Once dissolved, it is called an aqueous solution.
Salts do not conduct electricity as solids
Do conduct when melted (liquid) or aqueous
electricity is a flow of charged particles
Ions (charged atoms) are able to flow freely when in a liquid or aqueous state

7. Ionic Bonding Lattice Structure of NaCl Electricity
electrons in a metal wire ions in solution

8. 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-
Some 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:
The d-shell of the transition metals allow for multiple variations of valence electrons
Cu+
Cu2+

9. Xe Lewis-Dot Diagrams Lewis-Dot diagrams Also called:
electron-dot diagrams
Lewis-Dot Structures
Comprises of the Element symbol and the valence electrons
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.
Draw the Lewis Dot Structures for H, Ca, Al, C, Se, Br, and Ne Xe

11. 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-

12. 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

13. 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

14. 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

15. 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 - Ductility
- Malleability - good conductors of heat & electricity