1. Periodic Trends

2. Goal of the class
To understand the trends that exist within the periodic table.
Question of the day: How many atoms are in 55g of Iron?
Previous question: How many atoms are in 55g of Iron?

3. Mole The atomic mass can be used to find an amount of atoms
The unit used for the amount of atoms is a mole
Uses Avogadro's number, NA = 6.02x1023
Example: 12 grams is 1 mole of carbon
Different elements, different mass for moles

4. Example What would be the mass of one mole of water?
How many atoms are in one mole of water?
Molar mass = 18g / mol
There would be 3NA number of atoms 18x1023 atoms

5. Practice
If you had 88g of carbon dioxide, how many CO2 molecules would there be?
How many moles of CO2 is there in 88g?
Molar mass = 18g / mol
There would be 3NA number of atoms 18x1023 atoms

6. Periodic Table
The location in the periodic table can be used to predict the physical and chemical properties
Organized based on increasing atomic number
After one period chemical properties start to repeat
Elements on the left are the most metallic

7. Periods One row of the periodic table represents one period
As you move through the period, the number of valence electrons increases
Periods depend on electron orbital shells
Bottom row are part of periods 6 and 7
lanthanides and actinides

8. Periodic Table
lanthanides and actinides

9. Groups Also called families
Atoms within the same groups will have similar chemical properties
Have the same number of valence electrons
Valence electrons give it chemical properties
lanthanides and actinides

10. Electronegativity
Electronegativity is the measure of how strong an atom will pull an electron towards it
Fluorine has the highest electronegativity
Increases as atoms get smaller or fuller electron shells
Helps determine chemical reactivity
lanthanides and actinides

11. Ionization energy
Ionization energy is the amount of energy needed remove an electron from an atom.
Lower energy means the electrons are more easily removed
Helps determine the chemically reactivity of the atom or compound
lanthanides and actinides

12. Vocabulary
Mole – SI unit of an amount of a substance based on Avogadro's number
Avogadro’s Number – NA = 6.02x1023 used for calculating number of atoms in 1 mole.
Refractory – A substance that is resistant to heat

13. Vocabulary
Metallic – Made of, appearing to be made of, resembling, or related to metal
Electronegativity – the tendency or measure of an atom to attract and form bonds
Ionization energy– The energy needed to remove an electron from an atom or molecule to infinity

14. Homework Read: Chemical Building Blocks page 88-89
Please complete Chemical Building Blocks workbook page 36-38