Catalyst – September , What is an ion? 2. What are the 2 types of ions? 3. Fill in the blanks: ___________ electrons are those that interact to form chemical ________s.

Today’s Agenda  Catalyst  Review of Friday  Octet Rule and Stable Ions  Properties of Ionic Compounds (tom)  Exit Question, Tests, and Progress Reports

Today’s Objectives  SWBAT use the octet rule to predict the stable ion an atom will form in a chemical bond.  SWBAT describe the properties of ionic compounds. (tomorrow)

Review: What is a compound?  A compound results from interaction between valence electrons of different atoms.

Chemical Bond Spotlight: NaCl (table salt) 2 different elements:  Sodium (Na)  Chlorine (Cl) 1 compound:  Sodium chloride (NaCl) NaCl NaCl

Chemical Bond Spotlight: NaCl (table salt) Let’s see a video!

Review: Lewis Dot Structures Lewis Dot Structures only show the number of valence electrons in an atom.  Valence electrons are the only electrons involved in bonding  Valence electrons are the most important electrons

Review: Lewis Dot Sructures What do the Lewis Dot Structures have in common?!?!?

Review: Ions  An ion is an element that has gained or lost an electron. Cation = positive ion (+) Anion = negative ion (-) + -

Formation of Negative Ions (ANIONS)  Imagine that electrons are pieces of poop  Is poop is flying into your yard (an atom’s energy levels) a positive or negative thing?  So…if poop lands in your yard, are you more positive or more negative? So…NEGATIVE ions are formed when an atom GAINS one or more electrons! -

Formation of Positive Ions (CATIONS)  Imagine that electrons are pieces of poop  Is poop in your yard (an atom’s energy levels) a positive or negative thing?  So…if you get rid of the poop in your yard, are you more positive or more negative? + So…POSITIVE ions are formed when an atom LOSES one or more electrons!

Practice Questions 1. If an atom gains an electron it will have a ___________ charge. 2. If an atom loses an electron it will have a ___________ charge. 3. If chlorine gains 3 electrons it will have a _______ charge. NEGATIVE POSITIVE 3-

Ions! Cl loses 4 Electrons What is the ion formed?

Ions! Cobalt gains 2 electrons What is the ion formed?

Ions! Si 3- What happened… Gain or lose? How many?

Ions Si 3- Silicon gained 3 electrons How many total electrons does Si have now?

Practice Problems – Write all down!  Write down the ion that will form for the following: 1. Sr gains 5 electrons 2. Phosphorous loses 1 electron  Then, determine how many TOTAL electrons each ion will have after gaining or losing

Practice Problems – Write all down! How many TOTAL electrons do the following ions have? 1. Cl Li Xe O Zn 5-

Notes: Octet Rule  What is different about the valence shells of the elements on the Left and those on the Right?  The noble gases have full valence shells, the other atoms do not…

Key Point #1: The octet rule says that atoms are most stable when they have 8 valence electrons. 1. Atoms can gain or lose electrons to become stable (happy) 2. Atoms with 4 or more valence electrons will GAIN electrons to become stable (happy) 3. Atoms with 3 or less valence electrons will LOSE electrons to be stable (happy) Octet Rule

Octet Rule - Examples  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. F 2. O 3. N 4. H

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

Classwork Complete Half-Sheet and leave in group folder. Then, start working on HW Worksheet 6.3

Exit Question 1. Anion = _______ charge, Cation = _______ charge 2. What is the STABLE ION that will form for Lithium? 3. Draw the LDS for the following elements:  Sulfur  Magnesium HOMEWORK: Worksheet 6.3 AND Unit 2 RESUME!