Periodic table atomic radii, variation

A Figure 23.22 Variation in atomic radius of transition metals as a function of the periodic table group number. 

Fig. 9.54 The variation of atomic radius through the periodic table. Note the contraction of radius following the lanthanoids in Period 6 (following lutetimn, Z=71).

The variation of the first ionization energy through the periodic table is shown in Fig. 9.55, and some numerical values are given in Table 9.3. The ionization energy of an element plays a central role in determining the ability of its atoms to participate in bond formation (for bond formation, as we shall see in Chapter 10, is a consequence of the relocation of electrons from one atom to another). After atomic radius, it is the most important property for determining an element s chemical characteristics. 

Variation of atomic radii within a period of the periodic table. Equation (9.5) suggests that the radius of an atom is approximately proportional to For the main group elements, as we move from left to right across a period, is a constant and, as shown in Figure 9-8(a), Zeff increases rather significantly. Thus, the decrease in radius across the period is attributed to... 

Variation of atomic radii within a group of the periodic table. We have already established that electrons in the outermost shell of an atom are significantly screened by those in inner shells. Thus, for atoms closer to the bottom of the group, the outer electrons occupy orbitals that extend over much larger distances, and we expect the radius of an atom to increase from top to bottom within a group. 

---