Families of Element - The Search For Patterns Among The Elements, The Main-group Families, The Transition Metals - Hydrogen: The elemental orphan, Other families of elements
family periodic common chemical
A family of chemical elements usually consists of elements that are in the same group (the same column) on the periodic table. The term is also applied to certain closely related elements within the same period (row). Just as the individual members in a human family are all different but have common characteristics, like hair color, so to do the elements in a chemical family have certain properties in common, and others that make them unique.
When the elements are organized into families, hydrogen presents a problem. In some of its properties, hydrogen resembles the alkali metals, but it also shows some similarities to the halogens. Many periodic tables include hydrogen in group 1; others show it in groups 1 and 17. An alternative approach is to recognize hydrogen as being unique and not to assign it to a family.
In addition to the main-group families, other families of elements can be identified among the remaining elements of the periodic table.
Additional Topics
Johann Döbereiner (1780–1849) made one of the earliest attempts to organize the elements into families in 1829, when he observed that for certain groups of three elements, called triads, the properties of one element were approximately mid-way between those of the other two. However, because the number of elements known to Döbereiner was far less than it is today, the number o…
The similarity in electron configurations within a given main-group family results in the members of the family having similar properties. For example, the alkali metals are all soft, highly reactive elements with a silvery appearance. None of these elements is found uncombined in nature, and they are all willing to give up their single valence electron in order to form an ion with a charge of +1.…
At least two small family units can be identified within the larger transition-metal family. One of these small families, the coinage metals, consists of copper, silver and gold, the three elements in group 11. The other family, the platinum metals, includes elements from three groups: ruthenium and osmium from group 8; rhodium and iridium from group 9; and palladium and platinum from group 10. Th…
The lanthanides (or rare-earth elements) and actinides are two families that are related because they both result from electrons being added into an f sub-level. Both families have 14 members, the lanthanides consisting of the elements with atomic numbers 58 through 71, and the actinides including the elements with atomic numbers 90 through 103. However, it is sometimes convenient to consider lant…
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