The atomic number of each element increases by one, reading from left to right.Įlements are organised into blocks by the orbital type in which the outer electrons are found. Members of a group typically have similar properties and electron configurations in their outer shell.Ī horizontal row in the periodic table. But hexavalent chromium is toxic and carcinogenic, and trivalent chromium is mildly toxic in large quantities.A vertical column in the periodic table. Some chromates were used as pigments, but they are toxic so people do not want to use them anymore.Ĭhromium metal is nontoxic. It is also used in "chrome plating", where it makes things shiny and stops corrosion. The chromates and dichromates are what make chromium production areas toxic.Ĭhromium is used in different metal products. The chromium(III) oxide is reacted with aluminum to make chromium metal. The sodium dichromate is reduced by carbon to chromium(III) oxide. The sodium chromate is reacted with sulfuric acid to produce sodium dichromate. It is heated with sodium carbonate to make sodium chromate, iron(III) oxide, and carbon dioxide. Chromite is a mixture of iron(II) oxide and chromium(III) oxide. Occurrence and preparation ChromiteĬhromium occurs as chromite. Sodium dichromate, used in chromium processing.Hexavalent chromium can be destroyed by reacting it with reducing agents, turning it into Cr 3+ (trivalent chromium). It is found in places that make chromium metal, which is why they need to be cleaned up when they close. Hexavalent chromium compound Hexavalent chromium Īnother type of chromium ( Cr 6+ ( chromate, hexavalent chromium), in the +6 oxidation state) can cause cancer or make people sick, even though most people do not get exposed to it much. If we get too much of this type of chromium, it can harm our body. ![]() Chromium is also put into vitamins to make sure that we get enough. We get most of the chromium we need from our food we eat. If we do not get enough chromium, certain parts of our body may not work properly. One type of chromium ion ( Cr 3+, trivalent chromium ) is required by our body and by those of other animals. ![]() There are two main types of chromium ions, which are found in chromium compounds. Trivalent chromium compound Trivalent chromium Chromic acid is formed by dissolving chromium(VI) oxide in water. Chromium(VI) oxide, chromium trioxide, red, oxidizing agent, toxic.Chromium(IV) oxide, black, used in cassettes.Chromium(III) chloride, green when containing water (hydrated), purple when not containing water (anhydrous).Chromium(II) chloride, blue when dissolved in water, unstable.Chromium(II) oxide, black, rare, reducing agent. ![]() It forms chemical compounds that are colorful. It is reactive, but it reacts with air to produce a very thin coating of chromium(III) oxide, which prevents it from rusting any more.Ĭhromium occurs in several oxidation states +2, +3, and +6 are most common. ![]() Its ions have fewer electrons.Ĭhromium is a shiny metal. Most of the times it has 28 neutrons, but different isotopes have more or fewer neutrons. Its mass number (number of protons and neutrons) is about 54. It always has 24 protons, so its atomic number is 24. Its symbol on the periodic table (a list of all the elements) is Cr. Chromium metalĬhromium is a chemical element. Not to be confused with Chromium (web browser).
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