The periodic table of the elements is the most important tool that chemists use. Not only does it contain information specific to each element, but it also organizes the elements according to their physical and chemical properties. Each entry in the periodic table represents a single element and contains the element's chemical symbol, atomic number, and average atomic weight. The elements are arranged in vertical columns called groups and horizontal rows called periods. The elements within each group have similar chemical and physical properties.

The most basic information found on the periodic table is the classification of elements as metals, non-metals, or metalloids. You must be able to identify an element as one of these instantly. Some rules of the road and a bit of practice will help you do so.

Important Trends

• 1
  Metals are found on the left and bottom portions of the table. About ¾ of elements are metal.
• 2
  Nonmetals are found in the upper right portion of the table. About 1/5 of elements are nonmetals.
• 3
  Metalloids occupy the boundary between metals and nonmetals, weaving boron down to the right to tellurium. Only six elements are metalloids.