Catalyst – March 5+1-4, 2010 HOMEWORK OUT PLEASE! 1. What does the octet rule state? 2. How many electrons will oxygen want to gain or lose to have a full valence shell? 3. Do you think magnesium would be stable if it lost 3 electrons?

Today’s Agenda  Catalyst  Review  Properties of Ionic Compounds  Figure it out yourself: Ionization energy  Practice, Practice, Practice  Exit Question and Progress Reports

Today’s Objectives  SWBAT describe the properties of ionic compounds.  SWBAT explain trends in ionization energy across a periodic table.

Try the following on your own  How many electrons will the following atoms gain or lose to become stable (happy)? How many TOTAL electrons will the atom then have? What is the STABLE ION? 1. P 2. Kr 3. Ca 4. I 5. K

Exit Question 1. Anion = _______ charge, Cation = _______ charge 2. What is the STABLE ION that will form for the following elements? Write down the ion and how many electrons the atom will have TOTAL.  Te  Li 4. Draw the LDS for the following elements:  Sulfur  Magnesium

Videos Sodium in Water Formation of Sodium Chloride

Atoms  Some atoms are desperate to gain or lose electrons to fill out their octet!  But where do they get these electrons?  The electron store? NO!  Outer space? NO!  Wal-Mart? NO!  Other elements? YESSSSSSSSSS!!!!!!

Bonding  Key Point #1: There are two main ways an atom gains or loses electrons: By completely transferring them to another element – Ionic Bond By sharing electrons with another element – Covalent Bond Ionic this week, Covalent next week!

Ionic Bonds  When atoms come together through an ionic bond, it is called an ionic compound  They transfer electrons so everyone is happy!

Characteristics of Ionic Substances 1.Electrons are transferred 2.Bonds between metals and non- metals KNO 2 METAL NON-METAL

More Characteristics of Ionic Substances 3.They make crystals (usually solids, hard but can break) 4.High melting points 5.Good conductors of electricity when dissolved (soluble in water)

Who can think of practical applications? Why is tap water more conductive than distilled water?

Some practical applications… What is an electrolyte? Do you think that Gatorade would conduct electricity?electricity An electrolyte is basically just a salt dissolved in water…but it’s more about the IONS of the salt!

Even more practical!  Humans’ skin is slightly ionic because of sweat that is produced…  Let’s see how one innovator took this fact to make a really cool invention…

Ionization Energy Key Point #2: Ionization energy is the amount of energy it takes to remove a valence electron from an atom.  REMEMBER THE OCTET RULE!

1st IONIZATION ENERGY the energy required to remove the first valence electron from an atom

The 1 st ionization energy DECREASES as you go down a family

The 1 st ionization energy INCREASES across a period (right) (more p + have more pull on e - )

Multiple Ionization Energies  You are going to figure out a trend in multiple ionization energies.  This material is at a college level… but you guys are ready.  First things first, draw a Bohr model for four elements: Li, Be, B, C.

Ionization Energy IE 1 – 1 st Ionization energy IE 2 – 2 nd Ionization energy IE 3 – 3 rd Ion. en. etc…

Ionization Energy Can you figure out why there is such an increase in the red numbers? Use your BOHR models!! (10 mins) LiBe B C IE IE 2 7, IE 3 14, IE 4 25, IE 5 37,830

Do you get it?  Why does it take more energy to remove Lithium’s 2 nd electron than it takes to remove Carbon’s 4 th electron?  Hint: Start with a Bohr model

Ionization Energies Key Point #3: Breaking a full valence shell will cause a dramatic increase in ionization energy.

Exit Question 1. List 3 properties of ionic compounds. 2. Which has a higher FIRST ionization energy: sodium (Na) or francium (Fr)?