Anions common monatomic

Some common monatomic cations and anions and their names are given in Table 2.3. 

In addition to the common monatomic halide ions, numerous polyatomic species, both cationic and anionic, have been prepared. Many readers will be familiar with the brown triiodide ion, l3, formed from I2 and I ... 

Many ionic componnds are binary compounds, or compounds formed from just two elements. For binary componnds the first element named is the metal cation, followed by the nonmetallic anion. Thus NaCl is sodium chloride. The anion is named by taking the first part of the element name (chlorine) and adding -ide. Potassium bromide (KBr), zinc iodide (Znl2), and aluminum oxide (AI2O3) are also binary componnds. Table 2.2 shows the -ide nomenclature of some common monatomic anions according to their positions in the periodic table. 

TABLE 2.2 The "-ide" Nomenclature of Some Common Monatomic Anions According to Their Positions in the Periodic Table... 

Some common monatomic cations and anions and their names are given in Table 2.3. The rules for naming binary ionic compounds are illustrated by the following examples ... 

Table 3.4 also contains the polarizability volumes of some common monatomic ions. It is seen that removal of the most loosely held electron in an alkali metal atom leads to a dramatic reduction of the polarizability. Similarly, addition of an electron to a halogen atom to form an anion leads to an increase of the polarizability. Comparing cations and anion, we see that halogen anions have considerably higher polarizabilities than alkali metal cations. 

Table 9.1 lists some common monatomic and polyatomic anions (—). 

All common monatomic anions have noble gas configurations. Most monatomic cations of the representative elements (A groups) have noble gas configurations. The d- and /-transition elements form many compounds that are essentially ionic in character. Most d- and/-transition metal cations do not have noble gas configurations. 

Bases must have at least one lone pair on an atom to be able to form a new bond to H". Lone pairs on nitrogen and oxygen are the most common basic sites in molecules (e.g., NH3 and H2O). Anions, whether monatomic or polyatomic, typically have lone pairs that are basic examples are F , OH , and P04. ... 

The names and symbols of the common monatomic cations and anions are organized according to their charges in Figure 1.1. The names of many of the ions in the table include Roman numerals. These numerals are part of the Stock system of naming chemical ions and elements. You will read more about the Stock system and other systems of naming chemicals later in this chapter. 

A monatomic anion is named by changing the ending of the element s name to —ide, and adding the word ion. Thus, the anion of chlorine, CF, is called chloride ion. The anions of carbon, nitrogen, and oxygen (C , N . and O ) are called carbide, nitride, and oxide, respectively. Because there is only one possible charge for an ion formed from a nonmetal, it is unnecessary for the ion s name to specify its charge. Table 2.8 lists alphabetically a number of common monatomic ions. 

Some less common monatomic anions not mentioned in the previous discussion are hydride (H ), carbide nitride (N ), phosphide (P ) and sele-nide (Se ). Like the other monatomic ions discussed, these ions result from the elements gaining electrons so as to have an electron count equal to that of... 

The compounds described in Example 10-2 are binaty ionic compounds consisting of monatomic cations and monatomic anions. Commonly encountered ternary ionic compounds consist of monatomic and polyatomic ions. Bonding between atoms within the polyatomic ions is covalent. Some ternary ionic compounds are considered later in the chapter. 

FIGURE C.7 The typical monatomic anions formed by a selection of elements in the periodic table. Notice how the charge on each ion depends on its group number. Only the nonmetals form monatomic anions under common conditions. 

A number of general features in Table 1-3 is apparent. Complexes may be cationic, neutral or anionic. Ligands may be simple monatomic ions, or larger molecules or ions. Many ligands are found as related neutral and anionic species (for example, water, hydroxide and oxide). Complexes may contain all of the same type of ligand, in which case they are termed homoleptic, or they may contain a variety of ligand types, whereby they are described as heteroleptic. Some ligands such as nitrite or thiocyanate can coordinate to a metal ion in more than one way. This is described as ambidentate behaviour. In such cases, we commonly indicate... 

Whereas many metals form monatomic cations, only six nonmetallic elements commonly form anions. 

Common anions may be grouped as follows monatomic anions, oxyanions, and special anions. There are special endings for the first two groups the third group is small enough to be memorized. 

It is commonly assumed that (he independent cations end anions will behave as ideal monatomic gases with heat capacities (at constant volume) of R. m Born, M. Verhtirdl. Dent. Physlk. Ces. 1919. 21, 13 Haber, F. Ibid. 1919, 21. 750. 

Some compounds contain polyatomic ions that behave much like monatomic anions. Compounds that contain these ions are called pseudobinary ionic compounds. The prefix pseudo- means false these compounds are named as though they were binary compounds. The common examples of such polyatomic anions are the hydroxide ion, OH , and the cyanide ion, CN. The ammonium ion, NH4+, is the common cation that behaves like a simple metal cation. 

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