SCH 3U Chapter 2.1 Part A Ionic (1) PDF

Chapter #2: Chemical Bonding Part A: Ionic Bonding 2.1 The Formation of Ionic and Covalent Bonds Ionic Compounds Molecular Compounds Property Ionic Covalent Compound Compound State at room temperature Melting Point Electrical Conductivi...

Chapter #2: Chemical Bonding Part A: Ionic Bonding 2.1 The Formation of Ionic and Covalent Bonds Ionic Compounds Molecular Compounds Property Ionic Covalent Compound Compound State at room temperature Melting Point Electrical Conductivity as a liquid Solubility in Water Electrical Conductivity when dissolved in water Lewis Dot Diagrams (aka Electron Dot Diagrams) Lewis diagrams show only the valence electrons in an atom. They are useful because only the valence electrons interact when atoms bond to form molecules.  To Draw Lewis Structures: Write the element symbol. Around this draw dots, one for each valence electron. The dots should be spread over four sides. Dots are not paired until all sides have at least one dot. It doesn’t matter on which side dots are placed. For example, hydrogen can be drawn four ways: Lewis diagrams for the first 20 elements.  Chemical Bonds Atoms like to have their valence shells full. When two atoms combine, the valence electrons on each atom interact. A chemical bond forms between the atoms if their valence electrons make a new arrangement that has less energy than their previous arrangement. What is electronegativity? A measure of an atom’s ability to attract electrons in a chemical bond. Often abbreviated EN Electronegativity follows the same trend as ionization energy. Down a Group Across a Period Table of Electronegativities Range of Electronegativities Each element has numerical value for electronegativity. Most electronegative atom is________. Least electronegative atom is________. If the difference between electronegativities is: Greater than 1.7 Ionic compounds Less than 1.7 Covalent compound Covalent can be further divided into polar and non polar. When ΔIE is between 0 and 1.7 is polar and when ΔIE = 0 is non polar.  Range of Electronegativities. Identify each of the following bonds as ionic, covalent or polar covalent based on their electronegativities: Na-Cl H-O C-O Al-I Cl-Cl An excellent video about Ionic Bonding Ionic bonding How do Ionic Compounds Form? Bonding between Na and Cl using Lewis Diagrams 1. Draw the lewis structures of each atom involved in the bonding. 2. Use arrows to show transfer of electrons. 3. Re-write using square bracket, indicating charges.  Ion Joke Two hydrogen atoms bumped into each other recently. One said: "Why do you look so sad?" The other responded: "I lost an electron." Concerned, One asked "Are you sure?" The other replied "I'm positive."  Example #1: Represent the bonding between the following pairs of elements using Lewis Structures. a. Magnesium and Chlorine b. Aluminum and Fluorine c. Calcium and Oxygen Ionic Compounds Containing Transition Metals Transition Metals can have more than one valence. When working with a transition metal, enough info will be given to determine valence. Eg. FeO vs. Fe2O3 FeO Fe2O3 Crystal Lattices Example of a Crystal Lattice: NaCl Dissolving Ionic Compounds in Water When ionic compounds dissolve in water, the ions are pulled out of the crystal lattice and are surrounded by water.  Electrolytes When an ionic compound dissolves in water, the ions are free to move around in the water and are able to help the water to conduct electricity.  Homework P. 60#1- 9