The Periodic Table

The Periodic Table

1. The periodic table organizes all the elements according to their chemical properties. The metals are located on the left side and center of the table, and the non-metals are on the far right. In between are the metalloids. One exception is hydrogen. It is a non-metal, but it is located at the left side because it often behaves like a metal in chemical reactions.

   • Period
     • Each horizontal line or row is called a Period. The periods are numbered from 1 to 7. Hydrogen and helium make up the first period.
   • Group or Family
     • Each vertical column forms a Group or Family of elements, numbered from 1 to 18. Chemical families are groups of elements that have similar chemical and physical properties.
       • Group 1: Alkali Metals
         • Group 1 is located in the column at the far left of the table, and includes lithium, sodium, and potassium. Called the Alkali Metals, they are all soft, shiny, and silver in color, and very reactive with water. Their compounds tend to be white solids that are soluble in water. Recall a compound is a chemical combination of two or more elements in a specific ratio.
         • Group 2: Alkaline-Earth Metals
           • Group 2 includes magnesium and calcium. They are called the Alkaline-Earth Metals. They are shiny and silver but are not as soft as the Alkali Metals. Their compounds tend to be white, but they are less soluble than compounds formed by the Alkali Metals.
           • Group 18: Noble Gases
             • Group 18 is the far right column containing helium, neon, and argon. These are Noble Gases. They are very unreactive. Helium has a very low density, which is why helium-filled balloons float, and its non-reactivity means it cannot catch fire. Floating party balloons are filled with helium.
             • Group 17: Halogens
               • The elements in group 17, just to the left of the noble gases, are called the Halogens. This family of non-metals consists of the fluorine, chlorine, bromine, and iodine. These elements are poisonous and react readily with the Alkali Metals to form Salts, such as sodium chloride (table salt). Salts are compounds produced in neutralization reactions between acids and bases.
   • The periodic table is organized into rows and columns.