This is actually one of the chemical properties of metals and nonmetals: metals tend to form cations, while nonmetals tend to form anions. Second, most atoms form ions of a single characteristic charge. Thus, if you commit the information in Table 3. A few elements, all metals, can form more than one possible charge. Unfortunately, there is little understanding which two charges a metal atom may take, so it is best to just memorize the possible charges a particular element can have.
Note the convention for indicating an ion. The magnitude of the charge is listed as a right superscript next to the symbol of the element. An element symbol without a charge written next to it is assumed to be the uncharged atom. Naming an ion is straightforward.
If the element has more than one possible charge, the value of the charge comes after the element name and before the word ion. In print, we use roman numerals in parentheses to represent the charge on the ion, so these two iron ions would be represented as the iron II cation and the iron III cation, respectively.
For a monatomic anion, use the stem of the element name and append the suffix -ide to it, and then add ion. This is similar to how we named molecular compounds. Chemical formulas for ionic compounds are called ionic formulas.
A proper ionic formula has a cation and an anion in it; an ionic compound is never formed between two cations only or two anions only. The key to writing proper ionic formulas is simple: the total positive charge must balance the total negative charge. Because the charges on the ions are characteristic, sometimes we have to have more than one of a cation or an anion to balance the overall positive and negative charges.
It is conventional to use the lowest ratio of ions that are needed to balance the charges. Each ion has a single charge, one positive and one negative, so we need only one ion of each to balance the overall charge. When writing the ionic formula, we follow two additional conventions: 1 write the formula for the cation first and the formula for the anion next, but 2 do not write the charges on the ions.
The formula Na 2 Cl 2 also has balanced charges, but the convention is to use the lowest ratio of ions, which would be one of each. By convention, the formula is MgO. To balance the charges with the lowest number of ions possible, we need to have two chloride ions to balance the charge on the one magnesium ion.
Rather than write the formula MgClCl, we combine the two chloride ions and write it with a 2 subscript: MgCl 2. What is the formula MgCl 2 telling us? There are two chloride ions in the formula. Although chlorine as an element is a diatomic molecule, Cl 2 , elemental chlorine is not part of this ionic compound.
The chlorine is in the form of a negatively charged ion , not the neutral element. Naming ionic compounds is simple: combine the name of the cation and the name of the anion, in both cases omitting the word ion. Do not use numerical prefixes if there is more than one ion necessary to balance the charges. NaCl is sodium chloride, a combination of the name of the cation sodium and the anion chloride. MgO is magnesium oxide. MgCl 2 is magnesium chloride— not magnesium dichloride.
In naming ionic compounds whose cations can have more than one possible charge, we must also include the charge, in parentheses and in roman numerals, as part of the name. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.
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Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise. Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table. Fact box.
Group 11 Melting point Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements.
Appearance The description of the element in its natural form. Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Uses and properties. Image explanation. The symbol is based on the widely used alchemical symbol for silver.
Silver is a relatively soft, shiny metal. It tarnishes slowly in air as sulfur compounds react with the surface forming black silver sulfide. Sterling silver contains The rest is copper or some other metal. It is used for jewellery and silver tableware, where appearance is important. Silver is used to make mirrors, as it is the best reflector of visible light known, although it does tarnish with time.
It is also used in dental alloys, solder and brazing alloys, electrical contacts and batteries. Silver paints are used for making printed circuits.
Silver bromide and iodide were important in the history of photography, because of their sensitivity to light. Even with the rise of digital photography, silver salts are still important in producing high-quality images and protecting against illegal copying. Light-sensitive glass such as photochromic lenses works on similar principles. It darkens in bright sunlight and becomes transparent in low sunlight.
Silver has antibacterial properties and silver nanoparticles are used in clothing to prevent bacteria from digesting sweat and forming unpleasant odours. Silver threads are woven into the fingertips of gloves so that they can be used with touchscreen phones.
Biological role. Silver has no known biological role. Chronic ingestion or inhalation of silver compounds can lead to a condition known as argyria, which results in a greyish pigmentation of the skin and mucous membranes.
Silver has antibacterial properties and can kill lower organisms quite effectively. Natural abundance. Silver occurs uncombined, and in ores such as argentite and chlorargyrite horn silver.
However, it is mostly extracted from lead-zinc, copper, gold and copper-nickel ores as a by-product of mining for these metals. The metal is recovered either from the ore, or during the electrolytic refining of copper. Iron II. Iron III. Hydroxide OH -. Nitrate NO 3 -. Carbonate CO 3 Sulfate SO 4 Calcium carbide. CaC 2. The name of the element is derived from the Latin word for flint, silicis. In the form of silica SiO 2 or one of the silicates SiO 4 4- , it is found in many different minerals, including clay, quartz, zircon, feldspar, mica, zeolites, aluminosilicates, sand, etc.
It is also found in the gemstones opal, agate, rhinestone, and amethyst. Silicon is one of the most important elements on the periodic table at least from the perspective of computers!
Ultrapure silicon doped with boron or phosphorus is used as semiconductors in transistors, which are heavily employed in computers, solar panels, and other applications. Silica which is primarily silicon dioxide, SiO 2 , is used in the manufacture of glass. Silicones, which consist of chains of alternating silicon and oxygen atoms, are used in oils, lubricants, and silicone rubber.
Germanium is a hard, grayish white element with a metallic luster. The name of the element is derived from the Latin word for Germany, Germania. It is found in the Earth's crust at a concentration of 2 ppm, making it the 52nd most abundant element. It is found in the ores argyrodite [Ag 8 GeS 6 ] and germanite [Cu 13 Fe 2 Ge 2 S 16 ], but is more frequently obtained as a by-product of the refining of zinc.
Like silicon, germanium is used as a semiconductor, and is widely used in the computer industry. Silicon and germanium are both metalloids , having some characteristics of both metals and nonmetals. The existence of germanium was predicted by Dimitri Mendeleev in from a blank space in his periodic table beneath silicon; before it was actually found, the hypothetical element was referred to as "eka-silicon.
Tin is a soft, silvery-white metal. The name of the element is derived from the Anglo-Saxon word for the metal, while the chemical symbol "Sn" is derived from the Latin name for the metal, stannum. It is found in the Earth's crust at a concentration of 2 ppm, making it the 49th most abundant element. It is found in the ore cassiterite [tin IV oxide, SnO 2 ], and in trace amounts in other minerals. Elemental tin exists in two allotropic forms: above Structures made of tin that are cooled below Tin is easily purified in its metallic form from its ores, and has been known since prehistoric times.
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