Barium atomic radius

The atomic radii of the second row of d-metals (Period 5) are typically greater than those in the first row (Period 4). The atomic radii in the third row (Period 6), however, are about the same as those in the second row and smaller than expected. This effect is due to the lanthanide contraction, the decrease in radius along the first row of the / block (Fig. 16.4). This decrease is due to the increasing nuclear charge along the period coupled with the poor shielding ability of /-electrons. When the d block resumes (at lutetium), the atomic radius has fallen from 217 pm for barium to 173 pm for lutetium. 

Which has a larger atomic radius, silicon barium ... 

Barium s atomic radius is larger. Atomic size tends to increase from top to bottom and from right to left. Barium (Ba) is farther down and to the left on the periodic table than silicon (Si). Barium has more energy levels and is therefore larger. 

These are listed in Table 2.3 and shown in Figure 2.4. It will be seen that the atomic radii exhibit a smooth trend across the series with the exception of the elements europium and ytterbium. Otherwise the lanthanides have atomic radii intermediate between those of barium in Group 2A and hafnium in Group 4A, as expected if they are represented as Ln + (e )3. Because the screening ability of the f electrons is poor, the effective nuclear charge experienced by the outer electrons increases with increasing atomic number, so that the atomic radius would be expected to decrease, as is observed. Eu and Yb are exceptions to this because of the tendency of these elements to adopt the (+2) state, they have the structure [Ln +(e )2] with consequently greater radii, rather similar to barium. In contrast, the ionic radii of the Ln + ions exhibit a smooth decrease as the series is crossed. 

Barium has a body-centered cubic structure. If the atomic radius of barium is 222 pm, calculate the density of solid barium. 

Francium has a smaller atomic radius than cesium and radium is smaller than barium. Explain. (See Pyykko, P. C/iern. Rav. 1988, 88, 563-594.)... 

Problems 14.1 Francium has a smaller atomic radius than cesium and radium is smaller than barium. 

Problem Barium is the largest nonradioactive alkaline earth metal. It has a body-centered cubic unit cell and a density of 3.62 g/cm. What is the atomic radius of barium (Volume of a sphere V =... 

The radius of a barium atom is 0.224 nm. Barium adopts the A2 stmcture. Estimate the unit cell parameter of barium crystals. 

MetaUic barium has a body-centered cubic structure (all atoms at the lattice points) and a density of 3.51 g/cm. Assume barium atoms to be spheres. The spheres in a body-centered array occupy 68.0% of the total space. Find the atomic radius of barium. (See Problem 11.87.)... 

Ofthe elements calcium, Ca, beryllium. Be, barium, Ba, and strontium, Sr, which has the largest atomic radius Explain your answer in terms of trends in the periodic table. 

All of the elements are in Group 2. Of the four, barium has the highest atomic number and is farthest down the group. Therefore, barium has the largest atomic radius because atomic radii increase down a group. 

Barium has a density of 3.59 g/cm and crystallizes with the body-centered cubic unit ceU. Calculate the radius of a barium atom. 

Progressing down Group 2 from magnesium to barium, the atomic radius increases. This is due to the addition of an extra shell of electrons for each element as the group is descended. 

For example, metallic barium has a bcp lattice with a = 502.5 pm (Table 10.3.2). From these results, the metallic radius of Ba atom can be calculated ... 

Alkali-earth metals (calcium, barium, and magnesium) complex with polysaccharides extensively (Reisenhofer et al., 1984). Calcium has a smaller atomic and ionic radius than does sodium and, because it has two valence electrons, it is endowed with greater polarizing and bonding ability than Na+. Ca and Ca2+ easily form insoluble complexes with oxygenated compounds. Polysaccharide salts of alkali-earth metals are generally insoluble. 

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