Density of the elements

Chapter 30). Similar plots are obtained for the atomic and ionic radii of the elements and an inverted diagram is obtained, as expected, for the densities of the elements in the solid state (Fig. 2.2). 

The German physicist Lothar Meyer observed a periodicity in the physical properties of the elements at about the same time as Mendeleev was working on their chemical properties. Some of Meyer s observations can be reproduced by examining the molar volume for the solid element as a function of atomic number. Calculate the molar volumes for the elements in Periods 2 and 3 from the densities of the elements found in Appendix 2D and the following solid densities (g-cuU ) nitrogen, 0.88 fluorine, 1.11 neon, 1.21. Plot your results as a function of atomic number and describe any variations that you observe. 

The density of the elements is also an important parameter with regard to obtaining a high heat of combustion in a reactor of limited volume. The volumetric heat of combustion (kj m" ) shows differences compared to the mass-based heat of combustion (kj kg" ). For example, the volumetric heat of combustion of Zr is the highest of the fuel elements and that of Ti is the next highest when oxidized by oxygen gas. 

Figure 6.9 The density of the elements, arranged in lines by their period, and plotted against group number...

Bluish-black orthorhombic crystals refractive index 3.34 density of solid 4.933 g/cm3 at 20°C density of the element in liquid form at 120°C 3.96 g/cm melts at 113.6°C to a black mobile liquid the solid can be sublimed to vapor below its melting point vapor pressure of solid at 25°C 0.3075 torr vapor pressure at 113.6°C 90.5 torr the liquid boils at 184.3°C giving violet vapors vapor density 6.75 g/L critical temperature 545.8°C critical pressure 48.9 atm critical volume 155 cm /mol dielectric constant of solid 10.3 at 23°C and... 

FIGURE 16.5 The densities (in grams per centimeter cubed, g-cm 3) of the d-metals at 25°C. The lanthanide contraction has a pronounced effect on the densities of the elements in Period 6 (front row in this illustration), which are among the densest of all the elements. 

What is the density of the element copper (in grams per cubic centimeter) if a sample weighing 324.5 g has a volume of 36.2 cm3 ... 

Polymeric membrane elements and modules which consist of elements come in different sh4>es. The shape strongly determines the packing density of the element or module which is indicative of the available membrane filtration area per unit volume of the element or module the packing density, in turn, can affect the capital and operating costs of the membranes. The packing density is often balanced by other factors such as ease and cost of maintenance and replacement, energy requirements, etc. Most of the polymeric membranes are fabricated into the following forms tube, tubes-in-shell, plate-and-frame, hollow-fiber, and spiral-wound. 

The elements all crystallise with the b.c.c. lattice. The small radius of the tantalum atom (inferred from measurements on the metal) is reflected in the high density of the element. The metals all have high m.p. (c/. iron, p. 490). In every transition series the m.p. rise to a maximum at the Gp.VIA element and then fall and, as elements of the third transition series show the highest melting points, the m.p. of tantalum is exceeded by that of few other metals ... 

Physical properties reflect the change from individual molecules (N, P) to network covalent solid (As, Sb) to metal (Bi). Thus, melting points increase and then decrease. Large atomic size and low atomic mass result in low density. Because mass increases more than size down the group, the density of the elements as solids increases. The dramatic increase from P to As is due to the intervening transition elements. 

Melting points increase through Te, which has covalent bonding, and then decrease for Po, which has metallic bonding. Densities of the elements as solids increase steadily. 

The densities of the elements as liquids (at given T) increase steadily with molar mass. 

The kingdom plotted in terms of the densities of the elements as solids (including solidified gases). Note the very high densities toward the south in the vicinity of iridium and osmium. 

The densities of the elements K, Ca, Sc, andTi are 0.86,1.5,3.2, and 4.5 g/cm, respectively. One of these elements crystallizes in a body-centered cubic structure the other three crystallize... 

Molarity (atomic density) of the elements as pure crystals. J. Chem. Ed. 

Table 7.1. Mean atomic mass, van derWaals radius and van der Waals density of the elements of...

De Boisbaudian originally stated that the density of the element was 4.7 g/cm. Mendeleev had predicted a value of 5.9 g/cm and wrote to De Boisbaudran asking him to redetermine the value, which he did, obtaining a value close to the present value of 5.904 g/ciD . 

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