Chemical CharacteristicsĬhromium form variety of compounds and exists in many oxidation states, including +3, +6, +1. It is very dense metal and has a thermal conductivity of 93.9 W. Chromium has outstanding magnetic properties. It is resistant to tarnishing upon exposure with air. Chromium has a highly polishable texture. It is shiny, hard and brittle metal, that is easy to break. Physical CharacteristicsĬhromium is steel-gray in color. The annual production of chromite is about 28.8 million metric tons, which is primarily being used in the production of steel. Russia has deposits of the rare native form of chromium in Udachnaya Pipe, from which native chromium and diamonds are extracted. The largest producer of chromite is South Africa, followed by India, Brazil, Turkey, Finland and Kazakhstan. Volcanic activities also play important role in the distribution of chromium. Chromium is released in the environment by erosion of rocks that contain chromium. Chromite is the principal source of chromium that is used in pigments, worldwide. It is present in form of various ores, and the most common ore is iron chromium oxide FeCr 2 O 4, which is termed as chromite. Ĭhromium is the 13 th most abundant element in the Earth’s crust. Chromium has a distinct shine and forms various compounds in different colors that include green, purple, black, yellow, and orange. The name was given to this metal as it exists in diverse colors and was suggested by, Antoine Francois de Fourcroy (1755-1809) and René-Just Haüy (1743-1822). The name chromium has been derived from Greek word, chroma, which means color. Later, chromium was discovered as a novel, and isolated metal by Louis-Nicolas Vauquelin in 1797. History and DiscoveryĬhromium was initially discovered in red crystalline mineral form, known Siberian red lead, by Johann Gottlob Lehmann (1766). It has a shiny surface that is resistant to corrosion and this quality makes its ideal for manufacturing and coating of wide range of material, including cars and bikes. It is important to recognize which numbering system is being used and to be able to find the number of valence electrons in the main block elements regardless of which numbering system is being used.Chromium is a transition metal that was discovered by Gottlob Lehmann in 1766. You will come across periodic tables with both numbering systems. In this numbering system, group 1A is group 1 group 2A is group 2 the halogens (7A) are group 17 and the noble gases (8A) are group 18. The elements in this group are also gases at room temperature.Īn alternate numbering system numbers all of the \(s\), \(p\), and \(d\) block elements from 1-18. We will learn the reason for this later, when we discuss how compounds form. These elements also have similar properties to each other, the most significant property being that they are extremely unreactive, rarely forming compounds. This group contains very reactive nonmetal elements. Group 7A (or 17) elements are also called halogens. It is important to recognize a couple of other important groups on the periodic table by their group name.
Remember, Mendeleev arranged the table so that elements with the most similar properties were in the same group on the periodic table. The same pattern is true of other groups on the periodic table. Once again, because of their similarities in electron configurations, these elements have similar properties to each other. Group 2A is also called the alkaline earth metals.
Although most metals tend to be very hard, these metals are actually soft and can be easily cut. Group 1A is also known as the alkali metals. Because of their similarities in their chemical properties, Mendeleev put these elements into the same group. The elements in 1A are all very reactive and form compounds in the same ratios with similar properties with other elements. This is what causes these elements to react in the same ways as the other members of the family. All of the 1A elements have one valence electron. A group is a vertical column of the periodic table. Remember that Mendeleev arranged the periodic table so that elements with the most similar properties were placed in the same group.
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