 Grab a note sheet off the center stool  Get out your Periodic Table.  Fill in the first FIVE questions

 Check your answers and then answer the rest of the questions based on this video. Check your answers and then answer the rest of the questions based on this video.  Intro to Ionic/Covalent Video Intro to Ionic/Covalent Video

 What is the “goal” of atoms? What makes them happy?  To achieve a filled valence shell.  How can atoms achieve this?  To do this, atoms must gain or lose electrons to form ions. Or others share electrons. ( both are forms of bonding)

They make an Ion- 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.

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

 What is an 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

 What is a Covalent Bond  S ome valence electrons are shared between atoms to achieve a “full” valence shell.

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

 Remember that valence electrons are the electrons in the OUTERMOST energy level.  We know this by looking at the groups on the Periodic Table.

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

 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.

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

 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.

 Subscripts determine the number of atoms of that element in the molecule.  Coefficients determine how many molecules you have.