The Periodic Table

The following sections are included:

• About the Author
• Contents
• Introduction

Here, in this treatise, Gentle Reader, you will be led through the world of the Periodic Table; a world even more exciting, more wondrous, more bizarre, than anything Lewis Carroll could have ever imagined.

In the early decades of modern chemistry, atomic mass (weight) of an element was a major topic for debate and heated dispute. The original Periodic Tables were constructed in terms of order of atomic mass. Any irregularities in order were excused away. With the discovery of atomic number and its use as the foundation of the modern Periodic Table, inorganic chemists seem to have largely ignored patterns in element isotopes. Not only do such patterns explain average atomic mass irregularities, but they reveal some fascinating nuclear chemistry. In addition, the shell model of the nucleus is important in the synthesis of new chemical elements…

This book cannot be a comprehensive compilation of all the periodic properties. And it is certainly not intended to be a turgid, endless, boring, collection of tabulated data and graphical plots. In this chapter, there will be a focus just upon four major parameters: electronegativity, ionization energy, electron affinity, and relativistic factors. But first …

The placement of hydrogen in the Periodic Table is still a cause of dissention. In some versions of the Periodic Table, uniquely among the elements, the hydrogen symbol appears twice. Here, the different proposed locations will be described and contrasted. Though all common versions of the Periodic Table place helium in Group 18, some chemists propose its placement should be in Group 2, based upon electron configuration…

In Chapter 3, the controversy around the placement of hydrogen (and, to a lesser extent, helium) was described. There is another controversial topic — more so, in fact — of the element choices for the two lower members of Group 3. Here, the issues will be described…

As will become apparent throughout this book, chemists can be very casual about the use or misuse of chemical terms. This lack of clear definitions even applies to the categorization of the elements themselves. In this chapter, a range of types of categorizations will be introduced and their meanings clarified…

Isoelectronicity is a concept widely used in chemistry — or often misused. It is difficult to think of a more ambiguous term. This chapter commences with a summary of the various ways in which isoelectronic has been used, together with the modifiers that have been applied to delineate its meaning in a specific context. After providing a consistent series of definitions, the richness of isoelectronic relationships, in all their forms, will be explored…

As will be seen in the subsequent chapters, there are a variety of linkages among the elements. In this chapter, the focus will be upon patterns and trends within a Group or a Period. This topic, by necessity, must be limited to a few selected examples…

In this chapter, we will deconstruct the monolithic block of transition metals. Traditionally, classification has been by Group, but there are far richer patterns and trends to be found. By using chemical criteria for assignment, a hybrid approach to categorizing and clustering transition metals offers many advantages. Nevertheless, ambiguities arise as to the assignments that we choose…

The early Periodic Tables displayed an eight-Group system. Though we now use an 18-Group array, the old versions were based on evidence of similarities between the elements in what we now label the Group (n) and the corresponding elements of Group (n + 10). In this chapter, these similarities will be explored in depth. It is shown that such linkages are not limited to the top members of each Group as earlier discussions have emphasized…

In 1999, Laing reported on a previously unrecognized relationship between elements in the lower right quadrant of the Periodic Table. He named these linkages the chemical “Knight’s Move” Relationship. The name was chosen as the linkages were between an element and the element one Period below and two Groups to the right, the classic knight’s move in the game of chess. In this chapter, we will look at some of these connections, focusing especially upon the double pairs…

Diagonal relationships in the Periodic Table were recognized by both Mendeléev and Newlands. More appropriately called isodiagonal relationships, the same three examples of lithium with magnesium; beryllium with aluminum; and boron with silicon; are commonly quoted. Here these three pairs of elements are discussed in detail, together with evidence of isodiagonal linkages elsewhere in the Periodic Table…

The short form of the conventional Periodic Table may be convenient and compact, but it results in a marginalization of the lanthanoids (and of the actinoids, covered in Chapter 13). Not only do they appear to be the orphan elements, but in undergraduate chemistry courses, if they are mentioned at all, they are dismissed in the closing lecture(s) of the course as being boring and of little interest. Yet this is not the case. In addition to some trends, there are also interesting and curious exceptions. Lanthanoid chemistry is most definitely worthy of study…

The location of the series of radioactive elements that we now call the actinoids was once a question in itself. These elements were first believed to be the commencement of a new d-block row, as a result of similarities to the chemistry of the corresponding elements above them. Then it was realized that they formed a new f-series of elements. However, it is sometimes overlooked that the earlier actinoids do indeed have strong resemblances to transition metals in their chemistry. This chapter also includes discussion of the post-actinoid elements as they fit better in this context…

Most chemists regard the ammonium ion as behaving much like an alkali metal cation. Likewise, cyanide ion shows similarities to halide ions. In this chapter, the similarities and differences of these polyatomic ions to their group analogues will be explored. In addition, some less-common “pseudo-element” ions will be introduced…

The following section is included:

• Index