Representative elements ionization energies

Fig. 2.12 Relative orbital energies of the elements hydrogen to sodium. Solid lines indicate one-electron orbital energies. Dashed lines represent experimental ionization energies, which differ as a result of electron-electron interactions.

Transition metals tend to have higher melting points than representative metals. Because they are metals, transition elements have relatively low ionization energies. Ions of transition metals often are colored in aqueous solution. Because they are metals and thus readily form cations, they have negative standard reduction potentials. Their compounds often have unpaired electrons because of the diversity of -electron configurations, and thus, they often are paramagnetic. Consequently, the correct answers are (c) and (e). 

It is clear from Table 2.8 that each ionization energy is larger than the one before. Also note that the last two ionization energies of an element are always larger than the others. The sudden rise follows because the last two energies represent the removal of the two 1 s electrons removal of electrons from the 2s and 2p orbitals is easier. 

In the same chapter (Chapter 5), as an introduction to the paragraphs dedicated to the various groups of metals, the values relevant to a number of elementary properties have been collected. These are atomic properties (such as metallic and ionic radii, ionization energies, electronegativities, Mendeleev number, chemical scale, Miedema parameters, etc.), crystal structure and lattice parameters data of the allotropes of the elements, and selected thermodynamic data (melting and boiling temperatures and enthalpies, etc.). All these data indeed represent reference values in the discussion of the alloying behaviour of the elements. 

Figure 4.12 First ionization energies for the first five periods of representative elements. All units are in angstroms.

Recall that metals tend to lose electrons. Thus, the lower the ionization energy, the more reactive the metal. For a group of metals, reachvity increases as the atomic number increases. The opposite is true for nonmetals because nonmetals tend to gain electrons. The higher the ionization energy of a non-metal, the more reactive the nonmetal. For a group of nonmetals, reactivity decreases as the atomic number increases. Of the representative elements, which is the most reactive metal Which is the most reactive nonmetal (Hint What is the trend for ionization energy across a period )... 

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