Essential Questions: What are the processes by which different atoms come together to form new compounds and what forces hold solutions of these compounds/molecules together?

 An atom with a charge  Positive: cation  Negative: anion How do these atoms become charged?

 Electrons in the highest occupied energy level  The number of valence electrons greatly determines chemical properties of an element and how it will react How can we find the number of valence electrons in an element?

Electron configuration for chlorine: 1s 2 2s 2 2p 6 3s 2 3p 5 What is the highest energy level reached? 3 How many electrons are there? 7

Looking at the electron configuration for elements in the same group, they will all have the same number of valence electrons (just the A groups though! Not the B groups.)

How many valence electrons are there in the following elements? Chlorine Calcium Aluminum Carbon Neon

 Also known as Lewis Structures  Diagrams that represent the number of valence electrons in the atom 1. Find number of valence electrons 2. Write element symbol 3. Fill valence electrons around symbol, one on each side first then double up

Find the Lewis Dot Structures for the following elements: Chlorine Calcium Aluminum Carbon Neon

 Noble gases are the most stable elements on the Periodic Table due to the fact that they have 8 valence electrons (a complete outer shell)  Atoms will either lose or gain electrons through bonding in order to attain those complete 8 configurations  Metal elements tend to lose electrons while nonmetals tend to gain

 How do cations form?  Losing valence electrons ▪ Who tends to form cations?  How do anions form?  Gaining valence electrons ▪ Who tends to form anions?

 Metals  Lose valence electrons Example: Calcium Normal calcium calcium ion20 protons 20 electrons18 electrons no charge+2 charge

 Nonmetals  Gain electrons to get to an octet Example: Chlorine normal chlorinechlorine ion17 protons 17 electrons18 electrons no charge-1 charge

 Composed of a cation and an anion  Held together by ionic bonds  Represented by a chemical formula  A formula unit is the lowest whole-number ratio of ions in an ionic compound

 When writing the formulas, use the criss- cross method Mg +2 Cl -1 MgCl 2

 A chemical electrostatic force between a cation and an anion.  Can you have two cations come together? Two anions?

 For the following pairs of elements, write the formula for the ionic compound formed Aluminum and Chlorine Sodium and Sulfur Nitrogen and fluorine

 Why are ionic compounds composed of ions but have no charge overall?

 Most are crystalline solids at room temperature  Generally have high melting points  Can conduct electric current when melted or dissolved in water

 Finish the two worksheets and complete the ionic review questions on a left page of your notebook.