The Anatomy of the Periodic Table

 

    As you are probably well aware, in the periodic table, elements are arranged in order of increasing atomic number. The 18 vertical columns of the table are called groups or families, while the seven horizontal rows are called periods and correspond to the seven principal quantum energy levels, n = 1 through n = 7.

 

 

    On the right side of the periodic table is a dividing line resembling a staircase. To the left of the staircase lie the metals, and to the right of the staircase lie the nonmetals. Many of the elements that touch the staircase are called metalloids, and these exhibit both metallic and nonmetallic properties. Study the diagram below and memorize the names of the different types of elements, because you will definitely see questions about these groupings on the test!

 

 

    Metals are malleable, ductile, and have luster; most of the elements on the periodic table are metals. They oxidize (rust and tarnish) readily and form positive ions (cations). They are excellent conductors of both heat and electricity. The metals can be broken down into several groups.

 

    Transition metals (also called the transition elements) are known for their ability to refract light as a result of their unpaired electrons. They also have several possible oxidation states. Ionic solutions of these metals are usually colored, so these metals are often used in pigments. The actinides and lanthanides are collectively called the rare earth elements and are filling the f orbitals. They are rarely found in nature. Uranium is the last naturally occurring element; the rest are man-made.

 

    Nonmetals lie to the right of the staircase and do not conduct electricity well because they do not have free electrons. All the elemental gases are included in the nonmetals. Notice that hydrogen is placed with the metals because it has only one valence electron, but it is a nonmetal.

 

    Here are some specific families you should know about, within the three main groups (metals, nonmetals, and metalloids):

 

    Alkali metals (1A)—The most reactive metal family, these must be stored under oil because they react violently with water! They dissolve and create an alkaline, or basic, solution, hence their name.

    Alkaline earth metals (2A)—These also are reactive metals, but they don’t explode in water; pastes of these are used in batteries.

    Halogens (7A)—Known as the “salt formers,” they are used in modern lighting and always exist as diatomic molecules in their elemental form.

    Noble gases (8A)—Known for their extremely slow reactivity, these were once thought to never react; neon, one of the noble gases, is used to make bright signs.

 

    Now that you’re familiar with the different groupings of the periodic table, it’s time to talk about the ways we can use the periodic table to predict certain of elements.