Search results
Results from the WOW.Com Content Network
From left to right in the periodic table, the nonmetals can be divided into the reactive nonmetals and the noble gases. The reactive nonmetals near the metalloids show some incipient metallic character, such as the metallic appearance of graphite, black phosphorus, selenium and iodine. The noble gases are almost completely inert.
The dividing line between metals and nonmetals can be found, in varying configurations, on some representations of the periodic table of the elements (see mini-example, right). Elements to the lower left of the line generally display increasing metallic behaviour; elements to the upper right display increasing nonmetallic behaviour.
Periodic table extract showing the nonmetallic elements. H is normally placed over Li in Group 1. It is shown here over F for comparative purposes. The asterisks show further alternative positions for H. The elements shown as metalloids are those commonly recognized as such by authors who include such a class.
In the context of the periodic table a nonmetal is a chemical element that mostly lacks distinctive metallic properties. They range from colorless gases like hydrogen to shiny crystals like iodine. Physically, they are usually lighter (less dense) than elements that form metals and are often poor conductors of heat and electricity.
Periodic table of the chemical elements showing the most or more commonly named sets of elements (in periodic tables), and a traditional dividing line between metals and nonmetals. The f-block actually fits between groups 2 and 3 ; it is usually shown at the foot of the table to save horizontal space.
Some textbooks use the term nonmetallic elements such as the Chemistry of the Non-Metals by Ralf Steudel, [25]: 4 which also uses the general definition in terms of conduction and the Fermi level. [ 25 ] : 154 The approach based upon the elements is often used in teaching to help students understand the periodic table of elements, [ 26 ...
The metallic elements in the periodic table located between the transition metals to their left and the chemically weak nonmetallic metalloids to their right have received many names in the literature, such as post-transition metals, poor metals, other metals, p-block metals, basic metals, and chemically weak metals.
Some allotropes, particularly those of elements located (in periodic table terms) alongside or near the notional dividing line between metals and nonmetals, exhibit more pronounced metallic, metalloidal or nonmetallic behaviour than others. [508] The existence of such allotropes can complicate the classification of the elements involved. [509]