Rubidium atomic weight

A similar activity is found in Mendeleevs first attempt at a periodic system as presented in a hand-written table. If one examines the calculations that he is carrying out one finds again an attempt to compute differences between the atomic weights of elements in the columns of his table. For example Mendeleev writes the number 27 in smaller writing below the symbols for potassium (Zn - K = 65 - 39 = 27) and again below rubidium (Cd-Rb = 112-85 = 27). 

Aston EW (1932) The isotopic constitution and atomic weights of cesium, strontium, lithium, rubidium, barium, scandium and thallium. Proc Roy Soc A 134 571 Bach RO (ed) (1985) Lithium—Current Applications in Science, Medicine, and Technology. Wiley-Interscience, New York... 

A remarkable property of the atomic weights was discovered, in the sixties, independently by Lothar Meyer and Mendeleeff. They found that the elements could be arranged in rows in the order of their atomic weights so that similar elements would be found in the same columns. A modernised form of the Periodic Table will be found on pp. 106, 107. It will be noticed, for example, that the "alkali" metals, Lithium, Sodium, Rubidium and Caesium, which... 

Less attention has been paid to the reaction of cellulose with rubidium hydroxide and with cesium hydroxide. Heuser and Bartunek101 isolated adducts of rubidium hydroxide and of cesium hydroxide that had the general formula MOH 3 C Hi0Ot. Their studies showed that the concentration, in weight percent, of alkali metal hydroxide required for forming a stable adduct of the lowest alkali content increases with increase in the atomic weight of the metal Li < Na < K < Rb < Cs. However, on a molar basis, this relationship does not hold. No simple relationship exists between the size of cation and the concentration of hydroxide necessary for the formation of a stable adduct. 

Atomic Weight.—Like the other alkali-metals, rubidium is univalent, forming compounds of the type RbX, so that its hydrogen equivalent... 

Investigator. Number of Experiments. Mean Values of Ratios determined. Atomic Weight of Rubidium. 

The most reliable results are those of Archibald shown in heavy-face type, the mean value for the atomic weight of rubidium being 85-448. ... 

Atomic Weight.—The chemical properties of caesium indicate its close relationship to the other alkali-metals. It is univalent, forming compounds of the type CsX, its atomic weight and hydrogen equivalent being the same. Its atomic weight is of the order Cs =133 a value conformed by the specific-heat method (Vol. I., p. 88) by the isomorphism of the caesium compounds with those of potassium, ammonium, and rubidium (Vol. I., p. 74) by the correspondence of the properties of the metal and its compounds with the periodic system by the formation of a univalent cation and by the depression of the freezing-point of bismuth chloride and mercuric chloride produced by caesium chloride. 

The atomic weight of rubidium is 85.4678 amu. The two naturally occurring isotopes of rubidium have the following masses 85Rb 84.9118 amu 86.9092 amu. Calculate the percent of Rb in naturally occurring rubidium. 

All members of I,ho group form several oxides and u surprising amount, of uncertainty exists concerning them. They probably nil form the simple oxide M20 by direct, union of the elements, but then is seme doubt in the case of rubidium. These oxides nnet with wider forming the characteristic liases MOir, whose strength increases with iiicn iise in atomic weight. 

If the atomic volumes of the elements were plotted against the atomic weights, a series of waves was produced, rising to sharp peaks at the alkali metals sodium, potassium, rubidium, and cesium. Each fall and rise to a peak corresponded to a period in the table of elements. In each period a number of physical properties other than atomic volume also fell and rose. (See Figure 15.)... 

Rubidium has two naturally occurring isotopes, rubidium-85 (atomic mass = 84.9118 amu abundance = 72.15%) and rubidium-87 (atomic mass = 86.9092 amu abundance = 27.85%). Calculate the atomic weight of rubidium. 

Another attempt was made in 1888, by B.N. Tchitcherin. This author has placed the periodicity issue in the first place, but had investigated only the alkaline metals. Firstly, he noted the simple relations existent between atomic volumes of the all alkaline metals these relations can be expressed by the formula A(2-0.00535An), where A is the atomic weight, and n equals to 8 for lithium and sodium, 4 for potassium, S for rubidium and 2 for cesium. 

Atomic weight of rubidium 85.4678 Atomic weight of caesium 132.9055... 

Elements which are similar as regards their chemical properties have atomic weights which are either of nearly the same value (platinum, iridium, osmium), or which increase regularly (potassium, rubidium, caesium). 

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