Ionic & Covalent Bonding Notes | Chemistry PDF

PEIRCE SECONDARY SCHOOL Name: _________________________ ( ) Class: _______ Date: _____________ Objectives for Chemistry 5086/5088: 3.1 Ionic Bonding (c) relate the physical properties (including electrical property) of ionic compounds to their lattice structure. 3.2 Covalent Bonding relate the p...

PEIRCE SECONDARY SCHOOL Name: _________________________ ( ) Class: _______ Date: _____________ Objectives for Chemistry 5086/5088: 3.1 Ionic Bonding (c) relate the physical properties (including electrical property) of ionic compounds to their lattice structure. 3.2 Covalent Bonding relate the physical properties (including electrical property) of covalent substances to their structure and bonding. What do I already know ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ Questions Notes Are all Properties of Ionic Substances Pg 75-77 substances that are Structural properties Page 76 soluble are ionic? What is the meaning of molten? Is it the addition of water? Ionic compounds have giant ionic crystal lattice structures. The lattice consists of alternating positive and negative ions. These ions are held together by electrostatic forces of attraction. PEIRCE SECONDARY SCHOOL  Due to this structure and bonding, it gives rise to the following properties. Properties of Ionic substances - Most Ionic compounds have high melting and boiling points. - Ionic compounds are physically hard but brittle. - Most ionic compounds are soluble in water BUT insoluble in organic solvents. - Ionic compounds conduct electricity in MOLTEN or when dissolved in water. Melting boiling points Pg 76 - In an ionic compound, the forces of attraction between the oppositely charged ions are strong. - A large amount of energy is needed to overcome these strong attractive forces to melt the ionic compound. - Ionic compounds have high melting points and high boiling points. Note: (1) Due to high melting and boiling points, most ionic compounds are solids at r.t.p. (2) recall in kinetic particle theory, the forces of attraction are OVERCOME, not break. Hardness Pg 76 - The strong forces of attraction between oppositely charged ins make ionic compounds resistant to deforming. - Ionic compounds tend to be hard, as these forces cause the ions to resist motion. - When enough force is applied, the ions move away from their lattice positions. Ions of the same charge approach each other. The repulsive forces between ions of the same charge become larger than the attractive forces. As a result, the lattice structure shatters. PEIRCE SECONDARY SCHOOL  Solubility Pg 77 - The hydrogen atom of the water molecules are attracted to the anion of an ionic compound while the oxygen atom of the water molecules are attracted to the cation of an ionic compound. - As a result, the ions are pulled from the lattice structure and the compounds dissolves to form an aqueous solution. -Most ionic compounds are soluble in water and insoluble in organic solvents. Electrical Conductivity Pg 77 - When an ionic compound is molten/dissolved in water, the ions are free to move and are able to carry electric charges to conduct electricity. - Ionic compounds conduct electricity when molten or in aqueous solution, but not in the solid state. PEIRCE SECONDARY SCHOOL Questions Notes Properties of simple covalent substances Pg 78-80 -Covalent substances exist in a wide range of structures.  -Simple covalent molecules are one such structure. What are the Physical Properties of simple covalent molecules Pg 78-80 physical properties of - Simple covalent molecules have low melting and boiling simple points - Most simple covalent molecules are insoluble in water covalent BUT soluble in organic solvents. molecules? - Most simple covalent molecules cannot conduct electricity. Structural properties Page 78 In a simple covalent molecule such as bromine, the atoms in the molecule are held by strong covalent bonds. However, the molecules are held by weak intermolecular forces of attraction. Only a small amount of energy is needed to overcome these weak intermolecular forces of attraction. Hence simple covalent substances are usually gases or liquids at room temperature and pressure. Melting point and Boiling Point Pg 79 - A small amount of energy is needed to overcome these weak intermolecular forces of attraction between molecules, hence these simple covalent substances have low melting and boiling points. - As the molecule gets larger, the intermolecular forces of attraction are stronger and so the melting and boiling points are higher. Eg: Iodine is a larger molecule than bromine, hence iodine is a solid while bromine is a liquid at room temperature pressure (r.t.p). PEIRCE SECONDARY SCHOOL Solubility Pg 79 -Simple covalent substances are usually insoluble in water and soluble  in organic solvents. Electrical Conductivity Pg 80 -Simple covalent molecules cannot conduct electricity. -Simple molecular structures do not have free moving ions or delocalized electrons to conduct electricity. -The electrons in the atoms are either used for bonding or are not shared. Bonding electrons are shared between atoms in the simple covalent substance. Exceptions: If the covalent substance is soluble in water (eg HCl- a type of acid), its aqueous solution conducts electricity due to the presence of mobile ions: H+ and Cl- PEIRCE SECONDARY SCHOOL