Periodic trends lattice energy

Importance of Lattice Energy Periodic Trends in Lattice Energy... 

There is experimental evidence that supports this trend. For example, hydration energies for M(II) ions of the first row transition metals exhibit a W-shaped pattern, as a result of crystal field stabilization superimposed on the expected periodic increase (Figure 7.6), consistent with this model. Likewise, the measured lattice energies of transition metal fluorides (MF2) display a very similar pattern. The predominance of low spin d6 complexes is also consistent with the model, as there is a significant difference in LFSE between spin states in favour of low spin in the model. However, there are concerns with the model that have attracted criticism for example, one might anticipate low spin d5 more often than is observed. However, it is a simple and sufficient model to use at a basic level. 

Figure 20.27 shows a plot of experimental lattice energy data for metal(II) chlorides of first row J-block elements. In each salt, the metal ion is high-spin and lies in an octahedral environment in the solid state. The double hump in Figure 20.27 is reminiscent of that in Figure 20.26, albeit with respect to a reference line which shows a general increase in lattice energy as the period is crossed. Similar plots can be obtained for species such as MF2, MF3 and [MFg], but for each series, only limited data are available and complete trends cannot be studied. 

FIGURE 8.4 Periodic trends in lattice energy as a function of cation or anion radius. 

Periodic Trends in Lattice Energy How the Model Explains the Properties 9.4 Bond Energy and Chemical Change Where Does Come From ... 

Figure 7 shows the residence times calculated for = 0 ps and ti = 4 ps as a function of the adsorption energy for water in contact with the model surface and also for water in contact with the mercury surface. Suppressing the contribution from short time oscillations leads to a substantial increase in the calculated residence time. The trends, however, are rather similar. Water near the mercury surface behaves differently from water near the surfaces described by model III where a linear correlation of residence time with adsorption energy is observed. The adsorption energy is obviously not the only parameter that determines the residence time. Lattice geometry, periodicity, corrugation, and the curvature of the interaction potential influence it as well. 

The lattice energy results from electrostatic interactions among ions, so its magnitude depends on ionic size, ionic charge, and ionic arrangement in the solid. Therefore, we expect to see periodic trends in lattice energy. 

Types of Bonding Three Ways Metals and Nonmetals Combine 277 Lewis Symbols and the Octet Rule 278 The Ionic Bonding Model 280 Why Ionic Compounds Form The Importance of Lattice Energy 280 Periodic Trends in Lattice Energy 281 How the Model Explains the Properties of Ionic Corrpounds 283... 

Lattice energy depends on the magnitudes of the charges and on the distance between them. For example, Lil, Nal, and KI all have the same anion (I ) and all have cations with the same charge (+1). The trend in their lattice energies (Lil > Nal > KI) can be explained on the basis of ionic radius. The radii of alkali metal ions increase as we move down a group in the periodic table ( LI < Na-r < k-h) [ W Section 7.6]. Knowing the radius of each ion, we can use Coulomb s law to compare the attractive forces between the ions in these three compounds ... 

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