The Metals in the Middle
Identify properties of some transition elements.
Distinguish lanthanides from actinides.
Groups 3–12 are called the transition elements and all of them are metals. Across any period from Group 3 through 12, the properties of the elements change less noticeably than they do across a period of representative elements.
Most transition elements are found combined with other elements in ores. A few transition elements such as gold and sil- ver are found as pure elements.
Transition elements provide the materials for many things including electricity in your home and steel for construction.
Review Vocabulary mass number: the sum of neu- trons and protons in the nucleus of an atom
The Iron Triad Three elements in period 4—iron, cobalt, and nickel—have such similar properties that they are known as the iron triad. These elements, among others, have magnetic prop- erties. Industrial magnets are made from an alloy of nickel, cobalt, and aluminum. Nickel is used in batteries along with cadmium. Iron is a necessary part of hemoglobin, the substance that transports oxygen in the blood.
Iron also is mixed with other metals and with carbon to cre- ate a variety of steels with different properties. Structures such as bridges and skyscrapers, shown in Figure 13, depend upon steel for their strength.
Which metals make up the iron triad?
Figure 13 These buildings and bridges have steel in their structure. Explain why you think steel is used in their construction.
The Iron Triad