| 单词 | alkali metal |
| 例句 | Among the solubility rules previously discussed is the statement: Carbonates, phosphates, borates, and arsenates—except those of the ammonium ion and the alkali metals—are insoluble. Chemistry 2019-02-14T00:00:00Z Initial calculations indicated that they could contain more than 280,000 tonnes of lithium, a silver-white alkali metal – enough for 10 years’ production. The curse of 'white oil': electric vehicles' dirty secret 2020-12-08T05:00:00Z One is that no photoredox catalyst provides a reductant comparable in strength to that of alkali metals such as lithium and sodium. Strong chemical reducing agents produced by light 2020-03-31T04:00:00Z Lithium, sodium and potassium, which nicely align in the table’s first vertical column — Group One, the alkali metals, with rubidium, cesium, and francium — all have one electron in their outer electron shell. Is It Time to Upend the Periodic Table? 2019-08-27T04:00:00Z He introduced the relatively small alkali metals, rubidium and caesium, to the mix, which produced solar cells that maintain performance at high temperatures for almost 21 consecutive days. Japan’s global connectors 2019-03-19T04:00:00Z The alkali metals all have a single s electron in their outermost shell. Chemistry 2019-02-14T00:00:00Z One promising candidate exploits vapours of alkali metals such as potassium, which allows conversion of almost all the energy used to excite the electrons, without heating problems. Dreaming of death rays: the search for laser weapons 2019-01-08T05:00:00Z Two of the strongest reductants are the alkali metals sodium and lithium. Strong chemical reducing agents produced by light 2020-03-31T04:00:00Z Close observers of nature noted that certain chemical elements like lithium, sodium and potassium — known today as alkali metals — were all soft and floated in water. Is It Time to Upend the Periodic Table? 2019-08-27T04:00:00Z Sodium is one of the alkali metals, a group of famously reactive elements. Why this popular chemistry experiment is a blast 2015-01-26T05:00:00Z Active metals such as the alkali metals and alkaline earth metals can reduce nitrogen to form metal nitrides. Chemistry 2019-02-14T00:00:00Z He explains that the careful packaging is necessary because caesium is an alkali metal, from the first column of the periodic table. The element that redefined time 2014-10-03T04:00:00Z The snag is lithium’s high chemical reactivity: it is part of the alkali metal group that includes sodium and potassium, stars of many a chemistry-class calamity. Caging the Li-ion 2014-09-11T04:00:00Z “This is the first clear case of an alkali metal not only losing its single easily ionized valence electron in bonding, but also ‘breaking into the core’ in its bonding with several fluorines.” A Basic Rule of Chemistry Can Be Broken, Calculations Show 2013-11-21T12:45:00.513Z Rubidium is the chemical element of atomic number 37, a rare soft silvery reactive metal of the alkali metal group. And Let There Be "Molecules" of Light 2013-10-14T20:45:24.920Z How do alkali metals differ from alkaline earth metals in atomic structure and general properties? Chemistry 2019-02-14T00:00:00Z Sacks says that after that incident he never forgot the trends in reactivity of the alkali metals, an important principle that’s often taught in high school and college. How to repel kids from science: By chaining curiosity in cuffs 2013-05-02T11:45:00.223Z Saltiness is a measure of the positively charged ions of alkali metals, notably sodium. Technology: The taste of things to come 2012-06-25T13:21:13.797Z A compound radical, NH4, having the chemical relations of a strongly basic element like the alkali metals. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z One look at the table, and chemists and middle school students alike grasp the way atoms arrange themselves in groups: alkali metals, noble gasses, halogens. Data Visualizations Are More Than Just Pictures 2012-02-22T18:16:56Z Why does the reactivity of the alkali metals decrease from cesium to lithium? Chemistry 2019-02-14T00:00:00Z Bases of the alkali metals give with it four series of salts; these are stable except in alkaline solutions, in which they absorb oxygen and turn brown. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z The sodium and potassium salts, when heated to 400� C., give oxalates and carbonates of the 669 alkali metals, but the magnesium, calcium and barium salts yield carbonates only. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 6 "Foraminifera" to "Fox, Edward" 2011-04-22T02:00:08.637Z The fluorides of the alkali metals, of silver, and of most of the heavy metals are soluble in water; those of the alkaline earths are insoluble. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z Bichromates.—The bichromates are usually of a red or reddish-brown colour, those of the alkali metals being readily soluble in water. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z In general, the alkali metals react faster and are more reactive than the corresponding alkaline earth metals in the same period. Chemistry 2019-02-14T00:00:00Z The alkali metal salts included potassium chloride, a salt substitute, and potassium benzoate, a preservative. Researchers Create Nanostructures, and Whip Up a Recipe, Too 2010-09-06T19:41:00Z The arsenites of the alkali metals are soluble in water, those of the other metals are insoluble in water, but are readily soluble in acids. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6 "Armour Plates" to "Arundel, Earls of" These salts are not only those formed by the alkali metals, sodium and potassium, but also those formed by the heavy metals and alkaline earths. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. It combines with chlorides of the alkali metals to form double salts, and also with barium, calcium, strontium, and magnesium chlorides. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" The properties of the alkali metals are similar to each other as expected for elements in the same family. Chemistry 2019-02-14T00:00:00Z The metallic borates are generally obtained in the hydrated condition, and with the exception of those of the alkali metals, are insoluble in water. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" The thioarsenites and thioarsenates of the alkali metals are easily soluble in water, and are readily decomposed by the action of mineral acids. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6 "Armour Plates" to "Arundel, Earls of" The common alkali metals which enter into the formation of soap are sodium and potassium. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. It does not burn, and does not support ordinary combustion, but the alkali metals and magnesium, if strongly heated, will continue to burn in the gas with formation of oxides and liberation of carbon. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" The alkali metals all react vigorously with water to form hydrogen gas and a basic solution of the metal hydroxide. Chemistry 2019-02-14T00:00:00Z It does not react with the alkali metals, but combines with magnesium at a low red heat to form a boride, and with other metals at more or less elevated temperatures. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" Having now given the principal reactions for the most important metals, we will proceed to the examination of the alkali metals, the alkaline earths, and some of the acid elements. The Elements of Blowpipe Analysis Chromic sulphate combines with the sulphates of the alkali metals to form double sulphates, which correspond to the alums. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Group I.: the alkali metals Li, Na, K, Rb, Cs, and also Ag, monovalent; Cu, monovalent and divalent; Au, monovalent and trivalent. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" In addition, this high reactivity makes it necessary to prepare the metals by electrolysis of alkali metal compounds. Chemistry 2019-02-14T00:00:00Z Heated with sulphuric acid and with nitric acid it is oxidized to boric acid, whilst on fusion with alkaline carbonates and hydroxides it gives a borate of the alkali metal. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" Ammonium, NH4.—This hypothetical compound is commonly classed among the alkali metals from its close resemblance to the members of this group. The Elements of Blowpipe Analysis Some metallic chlorides readily form double chlorides, the most important of these double salts being the platinochlorides of the alkali metals. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Unlike the alkali metals, their normal carbonates and phosphates are insoluble in water. An Elementary Study of Chemistry As in the case of the alkali metals, this is part of the emission spectrum of these elements. Chemistry 2019-02-14T00:00:00Z The residue contains the alkali metals generally, as chlorides or sulphates. A Text-book of Assaying: For the Use of Those Connected with Mines. Sodium.—Like potassium, this alkali metal is detected by the color which its salts give to the flame. The Elements of Blowpipe Analysis Sulphur, phosphorus, carbon compounds, 256 and the alkali metals react violently with the gas, taking fire with explosive decomposition. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" What properties have the alkaline-earth metals in common with the alkali metals? An Elementary Study of Chemistry These carbonates precipitate upon mixing a solution of soluble alkali metal carbonate with a solution of soluble salts of these metals. Chemistry 2019-02-14T00:00:00Z Sodium is the commonest of the alkali metals. A Text-book of Assaying: For the Use of Those Connected with Mines. The alkali metals, such as sodium, potassium, and lithium, do not color glass appreciably, but they have indirect effects upon the colors produced by manganese, nickel, selenium, and some other elements. Artificial Light Its Influence upon Civilization If we accept these two propositions, it follows that hydrogen can be replaced atom for atom by other elements not only by the hydrogens but by alkali metals, etc. Scientific American Supplement, No. 324, March 18, 1882 Write the general formula of an alum, representing an atom of an alkali metal by X and an atom of a trivalent metal by Y. 6. An Elementary Study of Chemistry The stability of the peroxides and superoxides of the alkali metals increases as the size of the cation increases. Chemistry 2019-02-14T00:00:00Z Before determining the quantities of the particular alkali metals present, it is best to convert them altogether, either into chloride or sulphate, and to take the weight of the mixed salts. A Text-book of Assaying: For the Use of Those Connected with Mines. However, there are applications where the reactivity of the alkali metals is an advantage. Chemistry 2019-02-14T00:00:00Z The other alkali metals and their salts also impart color to a flame. Chemistry 2019-02-14T00:00:00Z What properties have the metals of the magnesium family in common with the alkali metals; with the alkaline-earth metals? An Elementary Study of Chemistry Although it has some chemical reactivity that is similar to that of the alkali metals, hydrogen has many of the same chemical properties of a nonmetal with a relatively low electronegativity. Chemistry 2019-02-14T00:00:00Z Because of this charge increase, the atoms of the alkaline earth metals are smaller and have higher first ionization energies than the alkali metals within the same period. Chemistry 2019-02-14T00:00:00Z The higher ionization energy makes the alkaline earth metals less reactive than the alkali metals; however, they are still very reactive elements. Chemistry 2019-02-14T00:00:00Z Like the alkali metals, the heavier alkaline earth metals impart color to a flame. Chemistry 2019-02-14T00:00:00Z It has the property of combining with the sulphates of the alkali metals to form compounds called alums. An Elementary Study of Chemistry The next atom is the alkali metal lithium with an atomic number of 3. Chemistry 2019-02-14T00:00:00Z Unlike most salts of the alkali metals, many of the common salts of the alkaline earth metals are insoluble in water because of the high lattice energies of these compounds, containing a divalent metal ion. Chemistry 2019-02-14T00:00:00Z Both atoms, which are in the alkali metal family, have only one electron in a valence s subshell outside a filled set of inner shells. Chemistry 2019-02-14T00:00:00Z A salt is known to be an alkali metal fluoride. Chemistry 2019-02-14T00:00:00Z The name alkali metals is commonly applied to the family for the reason that the hydroxides of the most familiar members of the family, namely sodium and potassium, have long been called alkalis. An Elementary Study of Chemistry Zinc and cadmium have lower reduction potentials than hydrogen, and, like the alkali metals and alkaline earth metals, they will produce hydrogen gas when they react with acids. Chemistry 2019-02-14T00:00:00Z However, alkali metal salts generally are very stable and do not decompose easily when heated. Chemistry 2019-02-14T00:00:00Z The oxides of the alkali metals have little industrial utility, unlike magnesium oxide, calcium oxide, and aluminum oxide. Chemistry 2019-02-14T00:00:00Z They are called the alkaline-earth metals because their properties are between those of the alkali metals and the earth metals. An Elementary Study of Chemistry Like the alkali metals they have a strong affinity for oxygen, tarnishing in the air through oxidation. An Elementary Study of Chemistry The alkali metals have the largest atomic radii and the lowest first ionization energy in their periods. Chemistry 2019-02-14T00:00:00Z |
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