Periodic table of the elements, Inside front

I Periodic Table of the Elements Inside Front Cover... 

Periodic table of the elements. Inside front cover... 

A Periodic Table of the Elements with the Gmelin System Numbers is given on the Inside Front Cover... 

The discovery of the next two transuranium elements, americium (Z = 95) and curium (Z = 96), depended on an understanding of the correct positions in the periodic table of the elements beyond actinium (Z = 89). It had been thought that these elements should be placed after actinium under the d-transition elements. So uranium was placed in Group VIB under tungsten. However, Glenn T. Seaborg, then at the University of California, Berkeley, postulated a second series of elements to be placed at the bottom of the periodic table, under the lanthanides, as shown in modem tables (see inside front cover). These elements, the actinides, would be expected to have chemical properties similar to those of the lanthanides. Once they understood this, Seaborg and others were able to use the predicted chemical behaviors of the actinides to separate americium and curium. 

Let s take a more detailed look at the periodic table and discover its great symmetry and usefulness. (Refer to the periodic table of chemical elements reproduced on the inside front and back covers of this book.)... 

Other materials to aid your study include lists of standard symbols and abbreviations for variables, units, and subatomic particles, found in Appendix 2. A summary of the mathematical equations used in the book is presented in Appendix 3. The solutions to all Practice Problems and selected end-of-chapter problems are provided in Appendices 4 and 5, respectively. The selected end-of-chapter problem numbers are printed in red. A periodic table is printed inside the front cover of the book, and a table of the elements appears inside the back cover. Let these tools help you succeed ... 

The periodicity of properties of the elements with increasing atomic number may be effectively shown by arranging the elements in a table, called the periodic table or periodic system of the elements. Many alternative forms of the periodic system have been proposed and used. We shall base the discussion of the elements and their properties in this book on the simple system shown as Table 5-1 (it is also reproduced inside the front cover of the book). 

A modem version of the periodic table, with the elements arranged by atomic number, is shown in Figure 2.15 (see also inside front covct). Each entry lists the atomic number, atomic symbol, and atomic weight of an element Ibis is a convaiiait way of tabulating such information, and you should become familiar with using the pmodic table for that purpose. As we develop the subject matt of chemistry throughout the text, you will see how useful the periodic table is. 

There is no single best form of the periodic table since the choice depends on the purpose for which the table is used. Some forms emphasize chemical relations and valence, whereas others stress the electronic configuration of the elements or the dependence of the periods on the shells and subshells of the atomic structure. The most convenient form for our purpose is the so-called long form with separate panels for the lanthanide and actinide elements (see inside front cover). There has been a lively debate during the past decade as to the best numbering system to be used for the individual... 

In the periodic table, atomic masses are listed directly below the symbol of the element. In the table on the inside front cover of this text, atomic masses are cited to four significant figures. That ordinarily will be sufficient for our purposes, although more precise values are available (see the alphabetical list of elements on the inside back cover). 

The periodic table is a useful way to organize chemical properties. To help you see the patterns, the periodic table on the inside front cover of this book highlights the various groups of elements. As you learn more about chemical structure and behavior, you will discover the principles that account for similarities and differences in the chemical behavior of the elements. 

For purposes of chemical bookkeeping, it is unnecessary to know the isotopic molar masses and isotopic distributions of the elements. All we need to know is the mass of one mole of an element containing its natural composition of isotopes. These molar masses usually are included in the periodic table, and they appear on the inside front and back covers of this textbook. 

In Section 1.2, we learned a few of the properties of sulfur and of iron. Do we have to learn the properties of all 100 or so elements individually, or are there some ways to ease that burden For over 140 years, chemists have arranged the elements into groups with similar chemical characteaisiics, which makes it easier to learn their properties. This grouping of the elements has been refined to a high degree, and the modem periodic table is the result. A full periodic table is shown inside the front cover of this book. The elements numbered 104 and up in that table have only recently been produced and in such infinitely small quantities that their chemical properties are unmeasured. Therefore, we will almost totally ignore them in the remainder of this book. 

A current version of the periodic table is shown inside the front cover of this book. The only fundamental difference between this table and that of Mendeleev is that the current table lists the elements in order by atomic number rather than by atomic mass. The reason for this will become clear later in this chapter as we explore the electron arrangements of the atom. 

The atomic number (symbol is Z) of an element is defined as the number of protons in the nucleus. In the periodic table, elements are arranged in order of increasing atomic numbers. These are the red numbers above the symbols for the elements in the periodic table on the inside front cover. For example, the atomic number of silver is 47. 

When you need values of atomic weights, consult the periodic table or the alphabetical listing of elements, both found on facing pages inside the front cover. 

Atomic weights and atomic numbers of the elements, listed alphabetically, are given on the front inside cover of this text. The values are a composite of the best agreements among the tables in the websites listed below. Additional information about each element can be found jBrom various versions of the periodic. table. There are many available on the Web. Following are some recommended ones. In most, you can click on an element and obtain atomic weight and number and other properties such as isotopes, physical properties, and history of the element. 

Solution To calculate the molar mass of a compound, we need to sum all the molar masses of the elements in the molecule. For each element, we multiply its molar mass by the number of moles of that element in one mole of the compound. We find molar masses for the elements in the periodic table (inside front cover of the text). 

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