Chemical Reactions SNC 2D1 September 13th, 2011
Mining is chemistry! • Nickel tailings • Colour comes from red, iron-containing compounds • Sudbury mining industry
Physical & Chemical Properties • Physical properties are those that can be observed without changing the identity of the substance • EXAMPLES - Boiling point, colour, density, electric charge, length, luster, malleability, mass, melting point, solubility, resistivity, strength, viscosity, volume, etc. • Properties that describe how a substance changes into a completely different substance are called chemical properties • EXAMPLES - Reactivity, heat of combustion, flammability, enthalpy of formation, etc.!
Ionic Compounds • An ionic compound is a compound composed of oppositely charged ions • An ion is a charged particle formed from the loss or gain of one or more electros • A cation is a positively charged ion • An anion is a negatively charged ion • Valence electrons are the electrons in the outermost occupied energy level
How do Ionic Compounds Form? • One or more electrons from one atom are transferred to another atom • An ionic bond forms, creating a neutral compound • The loss and gain of electrons allows each atom to form a full outer energy level of electrons and, therefore, become more stable
Ionic Compounds • Ionic compounds are usually composed of the ions of a metal and one or more non-metals. • Let’s take a look at the periodic table • Where are the metals? • Where are the non-metals? • How can we figure out how many valence electrons there are?
Lewis Dot Diagrams In a Lewis dot diagram: • put the symbol of the element in the middle • draw dots for the electrons in the outer shell only
Let’s Look at Aluminum Bohr Rutherford Lewis Dot
Let’s Make Some More Lewis Dot Diagrams... Sulfur Magnesium Oxygen Sodium
Stable Octet • Atoms will always try to have a chemical reaction so that they have a stable octet, meaning that the outer orbital must be full
Naming Binary Ionic Compounds • A binary ionic compound is a compound composed of a metal cation and a non-metal anion. • Rules • The first part of the name always identifies the positive ion, which is the metal cation. Thus, this part of the name is the name of the metal. • The second part of the name always identifies the negative ion, which is the non-metal anion. The name of the non-metal ion always ends with the suffix –ide.
Ionic Bond with Sodium and Chlorine • Sodium donates an electron to become a positively charged cation • Chlorine accepts an electron to become a negatively charged anion • We name it sodium chloride