2.  Intro to Ionic/Covalent Video Intro to Ionic/Covalent Video

3.  What is the “goal” of atoms? What makes them happy?  To achieve a filled valence shell.  To do this, atoms must gain or lose electrons to form ions. Others share electrons.  Ion- an atom that has gained or lost an electron, and therefore has a positive or negative charge based on the number of electrons it has lost.

5.  If the difference in electronegativities is between:  1.7 to 4.0: Ionic  0.3 to 1.7: Polar Covalent  0.0 to 0.3: Non-Polar Covalent Example: NaCl Na = 0.8, Cl = 3.0 Difference is 2.2, so this is an ionic bond!

6.  Cation- positively charged ion  Anion- negatively charge ion

7.  Ionic Bond- complete transfer of 1 or more electrons from one atom to another (one loses, the other gains) forming oppositely charged ions that attract one another  Good Animation on Ionic Bonding Good Animation on Ionic Bonding

8.  Covalent Bond- some valence electrons are shared between atoms to achieve a “full” valence shell.

9. A bond can result from an overlap of atomic orbitals on neighboring atoms. Note that each atom has a single, unpaired electron. Cl HH + Overlap of H (1s) and Cl (3p)

10.  Remember that valence electrons are the electrons in the OUTERMOST energy level… that’s why we did all those electron configurations!  B is 1s 2 2s 2 2p 1 ; so the outer energy level is 2, and there are 2+1 = 3 electrons in level 2. These are the valence electrons!  Br is [Ar] 4s 2 3d 10 4p 5 How many valence electrons are present?

11.  2 Methods:  Draw up the Lewis Dot Structures.  Swap Charges (works only for ionic)  How to Make Ionic Bonds How to Make Ionic Bonds

12.  Step 1, determine the # of valence electrons (either through group # for first 18 or through looking at electron configuration)  If you can lose them, then you get a + charge. Why?  If you need them, you get a (-) charge. Why?  Step 2, Then write the Atomic Symbol, surrounded by the electrons represented as dots.

13.  Step 3, place the dot structures next to each other (metal first if ionic bond). Then exchange dots.

14.  Write each of the atoms with their charges.  Then swap the charges down to the front of the other atom to determine how many you need of each to balance out the charges.