in groups discuss:

1. How would you define a compound? Use some key vocabulary terms from the first chemistry test to help you.

2. If H2O and H2O2 are both compounds, how are they different?

3. How do atoms combine to form compounds?4. How do ionic bonds and covalent bonds differ?

How are they the same?5. Think back to our global warming project. What

compounds (greenhouse gases) have we already studied? Explain how the electrons move in order for each of the greenhouse gases to form. Label each greenhouse gas as an ionic or covalent bond.

8th Grade ScienceAdapted from http://sciencespot.net/

Section A: Complete the chart using a periodic table to help you.

Answer these questions:

An atom that gains one or more electrons will have a ____________________ charge.

An atom that loses one or more electrons will have a ____________________ charge.

An atom that gains or loses one or more electrons is called an ____________.

A positive ion is called a ______________ and a negative ion is called an _______________.

POSITIVE

NEGATIVE

ION

CATIONANION

“An-Eye-On”“Cat-Eye-On”

What is an ionic bond?

Atoms will transfer one or more ________________ to another to form the bond.

Each atom is left with a ________________ outer shell.

An ionic bond forms between a ___________ ion with a positive charge and a ________________ ion with a negative charge.

Example B1: Sodium + Chlorine Example B2: Magnesium + Iodine

ELECTRONS

COMPLETE

METALNONMETAL

Example B3: Potassium + Iodine Example B4: Sodium + Oxygen

Example B5: Calcium + Chlorine Example B6: Aluminum + Chlorine

What is a covalent bond?

Atoms ___________ one or more electrons with each other to form the bond.

Each atom is left with a ________________ outer shell.

A covalent bond forms between two _________________.

Example C1: Hydrogen + Hydrogen Example C2: 2 Hydrogen + Oxygen

SHARE

COMPLETE

NONMETAL

Example C3: Chlorine + Chlorine Example C4: Oxygen + Oxygen

Example C5: Carbon + 2 Oxygen Example C6: Carbon + 4 Hydrogen

Review Vocab…

• What is an oxidation number?• How is it determined?• What is a subscript? What does it tell you

about the atoms in the compound?• What is a chemical formula?

Oxidation Numbers• Same thing as typical charge an atom will have

once it has lost or gained electrons• Shortcut to writing chemical formulas:

1. Ca I 2. Ca+2 I1-

3. Ca+2 I1-

Ca1 I2

CaI2

Bond With A Classmate1. Purple = Cations ; Pink = Anions2. Find a classmate to “bond” with and together

decide on the correct chemical formula (use the oxidation numbers to help you!)

3. You will have to decide how many of each ion you need to make a STABLE IONIC BOND.

4. Record all bonds on your Date Book (data table)

5. Look at the box on your paper for helpful hints6. You will have 5 minutes to make as many

bonds as possible.

Oxidation #’s Backwards

Give me the oxidation state (charge) for each atom in the compound for the following chemical formulas:No Periodic Tables

Allowed!A. BaCl2

B. CaF2

C. Mg3N2

D. MgBr2

E. KClF. K2O

Compound Naming• What do the red elements represent?

What do the black elements represent?• What patterns in the naming of

compounds do you notice?• How would you cluster the compounds

into four categories?• Which of the compounds are covalent?• How are the covalent compounds names

different from the ionic ones?

Naming Covalent CompoundsGuidelines for Inorganic

Compounds1. In covalent compounds, the least

electronegative element comes first and its name is unchanged.

2. The more electronegative element comes second and takes on the –ide ending like in ionic bonds

3. Subscripts are represented by Greek prefixes

Example: H2O –dihydrogen monoxide

1 Mono-

2 Di-

3 Tri-

4 Tetra-

5 Penta-

6 Hexa-

7 Hepta-

8 Octa-

9 Nona-

10 Deca-

1. Metal and nonmetal: Name the metal and change the nonmetal to –ide

2. Transition metals and nonmetals: Use roman numerals to represent the charge and name the nonmetal using –ide

3. Polyatomic Ions : If positive are more like metals and come first, if negative are more like nonmetals and come second. They have their own names and oxidation numbers (see chart on back)

Naming Ionic Bonds Practice

1. What is the chemical formula for the compound that results when Magnesium and Chlorine combine? Use the lewis dot structures and the criss cross method to show how you get the same formula.

2. How do you name this compound?

Show me the formula1. Ammonium Chloride2. Potassium Nitrate3. Calcium hydroxide4. Sodium Oxide5. Copper (II) Sulfate

Name that Compound…1. NaCl2. NaCO3

3. NaOH4. NH4OH5. Fe2(SO4)3

Show me the formula1. hexaboron silicide2. chlorine dioxide3. hydrogen iodide4. iodine pentafluoride5. dinitrogen monoxide

Name that CompoundCan you use the inorganic guidelines for all of these?

1. CO2

2. N2O3. N2O4

4. CH4