Third period elements, 159 table

Table 7.2 Electron Configurations of Second and Third Period Elements...

One way to compare the properties of the representative elements across a period is to examine the properties of a series of similar compounds. Since oxygen combines with almost all elements, we will compare the properties of oxides of the third-period elements to see how metals differ from metalloids and nonmetals. Some elements in the third period (P, S, and Cl) form several types of oxides, but for simplicity we will consider only those oxides in which the elements have the highest oxidation number. Table 8.5 lists a few general characteristics of these oxides. We observed earlier that oxygen... 

Consider the oxides of the third-period elements (see Table 8.4) ... 

Table 9.4 lists ionization energies for the third-period elements. With minor exceptions, the trend in moving across a period (follow the colored stripe) is that atomic radii decrease, ionization energies increase, and the elements... 

TABLE 9.4 Ionization Energies of the Third-Period Elements (in kJ mol ) ... 

Referring to the periodic table as needed write electron config urations for all the elements in the third period... 

The simple trend in the formulas shown by the third-row elements demonstrates the importance of the inert gas electron populations. The usefulness of the regularities is evident. Merely from the positions of two atoms in the periodic table, it is possible to predict the most likely empirical and molecular formulas. In Chapters 16 and 17 we shall see that the properties of a substance can often be predicted from its molecular formula. Thus, we shall use the periodic table continuously throughout the course as an aid in correlating and in predicting the properties of substances. 

In Chapter 6 we saw that the chemical compounds of the third-row elements display a remarkable regularity. Return to Chapter 6 and reread Section 6-6.2. The same simple trend in chemical formulas is discovered in the second row of the periodic table. Now we have a basis for explaining why these trends are found. 

Thermal equilibrium, 56 Thermite reaction, 122 Thermometers, 56 Thiosulfate ion, 362 Third-row elements, 101 compounds, 102 physical properties, 102 properties, table, 101 Third row of the periodic table, 364 Thomson, J. J., 244 Thomson model of atom, 244 Thorium... 

Figure 22. Correlations between the interfacial term, AX, derived from Fig. 14, and the enthalpy of formation of the oxide MO, corrected for the work to break metal-metal bonds. I, II, in mean first, second, and third periods of the periodic table of elements. From Ref. 26, updated. (From R. Guidelli, ed, Electrified Interfaces in Physics, Chemistry, and Biology, p. 252, Fig. 3. Copyright 1992 Kluwer Academic Publishers. Reproduced with permission.)...

Which elements in the third period of the periodic table are likely to have unusually high ionization energies ... 

With Na, the electron configuration of which may also be described as [Ne s1, the third period begins. A similar situation is found for each of the other periods in the Table the number of the period is the principal quantum number of the least tightly bound electron of the first element (an alkali metal) of the period. A few more details of these questions and the characteristics of special points in the Periodic Table are discussed in following paragraphs. The electron configurations of all the elements are given in Chapter 5. 

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