2.53. Transition Metals http://www.ck12.org
and the alkaline Earth metals in group 2, the transition metals are much less reactive. They don’t react quickly with
water or oxygen, which explains why they resist corrosion.
Other properties of the transition metals are unique. They are the only elements that may use electrons in the next
to highest—as well as the highest—energy level as valence electrons. Valence electrons are the electrons that form
bonds with other elements in compounds and that generally determine the properties of elements. Transition metals
are unusual in having very similar properties even with different numbers of valence electrons. The transition metals
also include the only elements that produce a magnetic field. Three of them have this property: iron (Fe), cobalt
(Co), and nickel (Ni).
Q:How is the number of valence electrons typically related to the properties of elements?
A:The number of valence electrons usually determines how reactive elements are as well as the ways in which they
react with other elements.
Those Elements Down Under
Transition metals include the elements that are most often placed below the periodic table (the pink- and purple-
shaded elements in theFigure2.108). Those that follow lanthanum (La) are called lanthanides. They are all
relatively reactive for transition metals. Those that follow actinium (Ac) are called actinides. They are all radioactive.
This means that they are unstable, so they decay into different, more stable elements. Many of the actinides do not
occur in nature but are made in laboratories.
Summary
- Transition metals are all the elements in groups 3–12 of the periodic table. More than half of all elements are
transition metals. - Transition metals are typical metals, with properties such as a superior ability to conduct electricity and heat.
They also have the metallic properties of luster, malleability, and ductility. In addition, transition metals have
high melting and boiling points and high density. - The lanthanides and actinides are the transition metals that are usually placed below the main part of the
periodic table. Lanthanides are relatively reactive for transition metals, and actinides are radioactive.
Vocabulary
- transition metal: Metal in groups 3 to 12 of the periodic table that is hard and shiny and less reactive than
metals in groups 1 and 2.
Explore More
At the following URL, click on any two of the transition metals and read about their properties, atomic structure,
discovery, and uses. Then write a paragraph comparing and contrasting the two elements.
http://www.chemicalelements.com/groups/transition.html
Review
- What are transition metals?
- Describe properties of transition metals.
- How do transition metals differ from metals in groups 1 and 2? How are they different from all other elements?
- Identify the lanthanides and actinides.