The middle groups use B in their titles. Unfortunately, there was a slightly different system in place in Europe. To eliminate confusion the International Union of Pure and Applied Chemistry IUPAC decided that the official system for numbering groups would be a simple 1 through 18 from left to right. Many periodic tables show both systems simultaneously. Skip to main content. The Periodic Table.
Search for:. How has the English dictionary evolved over time? Summary The periodic table is arranged in order of atomic number A period is a horizontal row of the periodic table. A group is a vertical row of the periodic table. Each element has its own chemical symbol, made from letters. Only elements are found in the periodic table, never compounds. Although most metals tend to be very hard, these metals are actually soft and can be easily cut. Group 2A is also called the alkaline earth metals.
Once again, because of their similarities in electron configurations, these elements have similar properties to each other. The same pattern is true of other groups on the periodic table. Remember, Mendeleev arranged the table so that elements with the most similar properties were in the same group on the periodic table.
It is important to recognize a couple of other important groups on the periodic table by their group name. Group 7A or 17 elements are also called halogens.
This group contains very reactive nonmetal elements. The noble gases are in group 8A. These elements also have similar properties to each other, the most significant property being that they are extremely unreactive, rarely forming compounds.
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