metals


 * //Metals and the limitations of the metallic bonding model// **


 * Video**

Properties of Alkali Metals || media type="custom" key="22853926" Description of metallic bonding || media type="custom" key="23230258" What is an alloy? ||
 * media type="custom" key="22853920"


 * Common Misconceptions:**
 * The metallic bonding model has no limitations.
 * All metals are magnetic.
 * Alloys have the same properties as pure metals.
 * All metals are solid at room temperature.


 * Interesting Facts:**
 * Pure gold is 24 carat, 9 carat gold is 9/24th gold which means it's only 37.5% gold!
 * The mark EPNS found on some silverware cutlery stands for 'electroplated nickel silver'.
 * Australian 'silver' coins are actually made of an alloy that's 25% nickel and 75% copper. However, the early Australian 50 cent coins did contain silver, but as the price of silver rose, it became profitable to melt down these coins for their silver content. A 50 cent coin containing silver was worth as much as $9.
 * The metallic bonding model cannot fully explain the range of melting temperatures, densities and the differences in electrical conductivity of metals.
 * The bonding model does not explain the magnetic properties of cobalt, iron or nickel.


 * Resources:**
 * The crystal structures of all the elements from WebElements.
 * A metallic bonding activity from Halifax Region Schools Board (Canada).
 * An animation on chemical bonding from Teachers' Domain.