Slide 1

Worksheet from side counter FIND YOUR NEW SEAT Slide 2 Pass back work Extra credit slips: pass out Presentation grades posted 3 rd period: finish presentations Tests will be graded by the end of Tuesday Go over Wednesday Work ethic Slide 3 Demo intro to reactions Elements vs. compounds Vocab cards Practice Kahoot check Valence electrons: revisit Objective: how do elements make up compounds? Slide 4 Volunteer to keep track of elements and compounds demonstrated in the demo Slide 5 Work on part 1 of your worksheet ElementCompound Slide 6 Slide 7 15 minutes to finish practice problems with your neighbor Slide 8 Go to kahoot.it on your iPad/laptop Slide 9 How do you find the number of valence electrons an element has by looking at the periodic table? Slide 10 How many valence electrons in Carbon? Slide 11 How many valence electrons in Nitrogen? Slide 12 How many valence electrons in Beryllium? Slide 13 How many valence electrons in Sodium? Slide 14 How many valence electrons in Argon? Slide 15 Back of worksheet Finish by Wednesday (more HW will be assigned Wed, collect on Th/F) Slide 16 sheet of paper for bellwork quiz Homework (compound vs. element) Write name and date 10/29/2014 Slide 17 1. Is Xe an element, compound or diatomic element? 2. How many elements make up the compound Mg(SO 4 ) 2 ? 3. How many Sulfur atoms are there in the compound Mg(SO 4 ) 2 ? Slide 18 1. Is Xe an element, compound or diatomic element? 2. How many elements make up the compound Mg(SO 4 ) 2 ? 3. How many Sulfur atoms are there in the compound Mg(SO 4 ) 2 ? 4. How many Carbon atoms are there in the compound CH 3 COOCH 2 C 6 H 5 ? Slide 19 How do we go from elements on the periodic table to building compounds? We must first visit Lewis Dot Structures of single elements to determine how they will fit together. Slide 20 Look at the two pictures below. One is a Lewis Dot Structure of Sulfur and one is the Bohr model of Sulfur. How are they similar and how are they different? Slide 21 Each atom has 4 sides (top, bottom, left, right). Only 2 electrons can fit on each side. Place electrons 1 at a time clockwise or counterclockwise on each side before doubling up No more than 2 electrons can sit on one side of the atom Exceptions: Hydrogen and Helium only have 1 orbital These rules make it clear later on how atoms bond together Slide 22 Create Lewis Structures using beans With your partner: Create the Lewis structure for the elements on your note-taker using knowledge of valence electrons and the proper location of Lewis Dot electrons Once you have created it, draw it on your note- taker in the box indicated Slide 23 sheet of paper for bellwork quiz Write name and date 10-30-2014 Slide 24 Draw the Lewis dot structure of Iodine (I) How many electrons does Iodine need to have a full outer shell? How many electrons does Hydrogen need to have a full outer shell? Slide 25 What are the rules for how do Lewis Dot Structures bond together to make compounds? Slide 26 Slide 27 Slide 28 IN COMPOUNDS ELECTRONS COME IN PAIRS! Only in rare circumstances do you see a lonely electron on an atom in a compound Slide 29 Electronegativity the atoms desire for electrons or attraction to electrons Compare the following elements in terms of electronegativity: H vs. O C vs. O C vs. F B vs. F Slide 30 1. LEAST electronegative atoms usually go in the middle 2. More electronegative atoms like to have electron pairs un-bonded (floating around them 3. Hydrogens are always external (not central atoms) 4. Each atom must have a satisfied octet (8 valence electrons, 2 for hydrogen) Slide 31 Octet rule: atoms of main group elements tend to bond in such a way that each atom has 8 electrons in its valence shell. Bonds: each bond is a shared pair of electrons and each atom associated with that bond contains both electrons in its valence shell. Slide 32 1. Formal Charge = The charge on an atom based on its bonding configuration in a compound 2. Formal Charge = V B 2 V = valence electrons of element in question B = bonded electrons of element in question Ex. C 2 H 2 Element: Carbon V = 4B = 8 = 4 2 FC = 4 4 = 0 Slide 33 Goal: The structure of the compound must have the lowest possible formal charges on all atoms to be stable If formal charges are high, the compound likely does not exist in that form. Slide 34 Practice with beans Create the following compounds with your beans and then draw them on your note-taker in the box provided H 2 OCO 2 Slide 35 What would be a good definition for a bond after creating these structures? How many electrons would be required to make a double bond? A triple bond? Slide 36 Task: Step 1: add up all valence electrons for each atom in the compound Step 2: draw the Lewis Structure of the compound with electrons ONLY Step 3: draw the Lewis Structure of the compound by substituting bonds for electrons between atoms (2 electron = 1 bond, 4 electrons = 2 bonds, 6 electrons = 3 bonds) Slide 37 Task: Step 1: add up all valence electrons for each atom in the compound Step 2: draw the Lewis Structure of the compound with electrons ONLY Step 3: draw the Lewis Structure of the compound by substituting bonds for electrons between atoms (2 electron = 1 bond, 4 electrons = 2 bonds, 6 electrons = 3 bonds) Slide 38 Use the beans each time you create a compound If you need help with one, I cannot help you unless you have started with the beans so we can manipulate them Slide 39 Covalent bond: Shared pair of electrons Can be equal or unequal sharing polarity Ionic bond: Loss of gain of electrons in creating a bond Metal + non-metal (positive ion + negative ion) Slide 40 More Lewis Dot Structure Honors: formal charge with each atom in each compound!