Most elements are metals, rather than non-metals. Each element has its own chemical symbol, made from letters. Since the families of elements were organized by their chemical behavior, it is predictable that the individual members of each chemical family will have similar electron configurations.
Remember that Mendeleev arranged the periodic table so that elements with the most similar properties were placed in the same group. A group is a vertical column of the periodic table. All of the 1A elements have one valence electron. This is what causes these elements to react in the same ways as the other members of the family. The elements in 1A are all very reactive and form compounds in the same ratios with similar properties with other elements.
Because of their similarities in their chemical properties, Mendeleev put these elements into the same group. Group 1A is also known as the alkali metals. 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. David Drayer. Jul 30, Explanation: A group is a vertical column on the periodic table.
Related questions How do I determine the molecular shape of a molecule? What is the lewis structure for co2? Post-transition metals: Ahead of the jump into the nonmetal world, shared characteristics aren't neatly divided along vertical group lines. These elements have some of the classic characteristics of the transition metals, but they tend to be softer and conduct more poorly than other transition metals. Many periodic tables will feature a bolded "staircase" line below the diagonal connecting boron with astatine.
The post-transition metals cluster to the lower left of this line. They form the staircase that represents the gradual transition from metals to nonmetals. These elements sometimes behave as semiconductors B, Si, Ge rather than as conductors.
Metalloids are also called "semimetals" or "poor metals. Nonmetals: Everything else to the upper right of the staircase — plus hydrogen H , stranded way back in Group 1 — is a nonmetal. Halogens: The top four elements of Group 17, from fluorine F through astatine At , represent one of two subsets of the nonmetals.
The halogens are quite chemically reactive and tend to pair up with alkali metals to produce various types of salt. The table salt in your kitchen, for example, is a marriage between the alkali metal sodium and the halogen chlorine. Noble gases: Colorless, odorless and almost completely nonreactive, the inert, or noble gases round out the table in Group Many chemists expect oganesson, one of the four newly named elements, to share these characteristics; however, because this element has a half-life measuring in the milliseconds, no one has been able to test it directly.
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