Section 3:Transition elements

1. The Periodic Table Section 3:Transition elements

2. The Metals in the Middle • Groups 3-12—Transition Elements • Most are found combined with other elements • Some—like Au and Ag are found as pure elements

3. The Metals in the Middle • The Iron Triad • 3 elements in period 4—iron, cobalt, and nickel—have such similar properties that they are called the iron triad • Have magnetic properties • Nickel is used in batteries • Iron is essential in your body, and creates a variety of steels

4. The Metals in the Middle • Uses of Transition Elements • Most have higher melting points than the representative elements (?) • Tungsten- light bulb filaments • Mercury- thermometers • Chromium- paint • Ruthenium, thodium, palladium, osmium, iridium, and platinum are sometimes called the platinum group because they have similar properties and don’t combine easily with other elements • Often used as catalysts- substance that can make something happen faster but is not changed itself

5. Inner Transition Elements • There are 2 series of inner transition elements • From Cerium to Lutetium are the lanthanides • A.k.a. the rare earths • Usually combined with oxygen in Earth’s crust • From Thorium to Lawrencium are the actinides

6. Inner Transition Elements • The Lanthanides • Soft metals that can be cut with a knife • Very similar …so hard to separate • Crust contains more cerium than lead

7. Inner Transition Elements • The Actinides • All radioactive • Thorium, Protactinium, and Uranium are the only ones now found naturally on Earth • All others are Synthetic Elements- made in laboratories and nuclear reactors • Plutonium is used a s a fuel in nuclear power plants • Americium is used in smoke detectors • Californium is used to kill cancer cells

8. Inner Transition Elements • Dentistry and Dental Materials • Dentists have been using amalgam for over 150 years to fill cavities • Amalgam is a mixture of silver, copper, tin, and mercury and is know as the “silver filling” • People are concerned for their health • Today, there are alternatives • Orthodontists use new nickel and titanium alloys for the wires on braces • Have shape memory