Polyatomic ions compounds containing

Ionic compounds containing polyatomic ions. Ftitassium dichromate (KjCtjOj, orange), potassium permanganate (KMnOa, very dark purple), and potassium nitrate (KNO3. white). 

Compounds containing polyatomic ions follow similar rules. In sodium carbonate, there are two Na+ ions per carbonate ion, so its formula is Na2C03. When a subscript has to be added to a polyatomic ion, the ion is written within parentheses, as in (NH4)2S04, where (NH4)2 means that there are two NH4+ (ammonium) ions for each S042- (sulfate) ion in ammonium sulfate. In each case, the ions combine in such a way that the positive and negative charges cancel all compounds are electrically neutral overall. 

Ionic compounds containing polyatomic ions (Section 2.8) are named in the same way as binary ionic compounds First the cation is identified and then the anion. For example, Ba(N03)2 is called barium nitrate because Ba2+ is the cation and the N03 polyatomic anion has the name nitrate. Unfortunately, there is no systematic way of naming the polyatomic ions themselves, so it s necessary to memorize the names, formulas, and charges of the most common ones listed in Table 2.3. The ammonium ion (NH4+) is the only cation on the list all the others are anions. 

Try the following problems to practise writing formulas for compounds containing polyatomic ions. 

Finally, use the lowest ratio of subscripts if the compound is ionic, MgCl2. The crisscross method also works for compounds containing polyatomic ions. One note of caution, however when there are multiple units of a polyatomic ion present, you must use parentheses to indicate this fact. Using this... 

A great many compounds contain polyatomic ions ( many-atom ions). There are many polyatomic anions but relatively few polyatomic cations. The most important polyatomic cation is the ammonium ion, NH4 (compare with ammonia, NH3). Some of the most important polyatomic anions are listed in Table 5.2, the first seven of which are also presented in Figure 5.13, along with others. 

Compounds that contain polyatomic ions Many ionic compounds contain polyatomic ions, which are ions made up of more than one atom. Table 8-6 lists the formulas and the charges for several polyatomic ions. 

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. 

Write the name for each of the following compounds containing polyatomic ions. 

Polyatomic Ions Covalent Bonds Within Ions Many ionic compounds contain polyatomic ions, which consist of two or more atoms bonded covalently and have a net positive or negative charge. For example, the ionic compound calcium carbonate is an array of polyatomic carbonate anions and monatomic calcium cations attracted to each other. The carbonate ion consists of a carbon atom covalently bonded to three oxygen atoms, and two additional electrons give the ion its 2- charge (Figure 2.15). In many reactions, a polyatomic ion stays together as a unit. 

Ionic compounds containing polyatomic ions are not binary compounds, because they contain more than two elements. 

Naming ionic compounds containing polyatomic ions follows rules similar to those for naming binary compounds. 

So far in this chapter we have discussed only binary ionic compounds, which contain ions derived from single atoms. However, many compounds contain polyatomic ions charged species composed of several atoms. For example, ammonium nitrate contains the and N03 ions. 

Formulas for polyatomic ionic compounds Many ionic compounds contain polyatomic ions, which are ions made up of more than one atom. Table 7.9 and Figure 7.10 list the formulas and charges of common polyatomic ions. Also, refer to Table R-6 on page 970. A polyatomic ion acts as an individual ion in a compound and that its charge applies to the entire group of atoms. Thus, the formula for a polyatomic compound follows the same rules used for a binary compound. 

So far in this chapter we have discussed only binary ionic compounds, which contain ions derived from single atoms. However, many compounds contain polyatomic ions charged species composed of several atoms. For example, ammonium nitrate contains the NH4- and NOs ions. These ions with their opposite charges attract each other in the same way as do the simple ions in binary ionic compounds. However, the individual polyatomic ions are held together by covalent bonds, with all of the atoms behaving as a unit. For example, in the ammonium ion, NH4-, there are four N—H covalent bonds. Likewise the nitrate ion, NOs , contains three covalent N—O bonds. Thus, although ammonium nitrate is an ionic compound because it contains the NH4-and NO3" ions, it also contains covalent bonds in the individual polyatomic ions. When ammonium nitrate is dissolved in water, it behaves as a strong electrolyte like the binary ionic compounds sodium chloride and potassium bromide. As we saw in Chapter 7, this occurs because when an ionic solid dissolves, the ions are freed to move independently and can conduct an elearic current. 

A polyatomic ion is an ion that contains two or more elements. Compounds containing polyatomic ions are composed of three or more elements and usually consist of one or more cations combined with a negative polyatomic ion. In general, naming compounds containing polyatomic ions is similar to naming binary compounds. The cation is named first, followed by the name for the negative polyatomic ion. 

Rules for Naming Compounds Containing Polyatomic Ions... 

Write correct formulas for ionic compounds containing representative metals and polyatomic ions, and correctly name binary covalent compounds and compounds containing polyatomic ions. (Section 4.10)... 

The formulas and names of some common polyatomic ions are given in I Table 4.7. From this information, the formulas and names for compounds containing polyatomic ions can be written. The rules are essentially the same as those used earlier for binary ionic compounds. In the formulas, the metal (or ammonium ion) is written first, the positive and... 

Compounds containing polyatomic ions are present in many consumer products. 

When ionic compounds containing polyatomic ions dissolve in water, the polyatomic ions usually dissolve as intact units. 

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