Formulas for binary ionic compounds

Convert between names and chemical formulas for binary ionic compounds, ionic compounds with polyatomic ion(s), binary covalent compounds, binary acids, and oxyacids. 

Formulas for binary ionic compounds In the chemical formula for any ionic compound, the symbol of the cation is always written first, followed by the symbol of the anion. Subscripts, which are small numbers to the lower right of a symbol, represent the number of ions of each element in an ionic compound. If no subscript is written, it is assumed to be one. You can use oxidation numbers to write formulas for ionic compounds. Recall that ionic compounds have no charge. If you add the oxidation number of each ion multiplied by the number of these ions in a formula unit, the total must be zero. 

EXAMPLE) 5.4 ) Writing Formulas for Binary Ionic Compounds... 

Use the octet rule to correctly predict the ions formed during the formation of ionic compounds, and write correct formulas for binary ionic compounds containing a representative metal and a representative nonmetal. (Section 4.3)... 

Before you can write a chemical formula from the name of a compound, you need to recognize what type of compound the name represents. For binary ionic compounds, the first part of the name is the name of a metallic cation. This may include a Roman numeral in parentheses. The anion name starts with the root of the name of a nonmetal and ends with -ide. 

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. 

The bonding between the atoms within polyatomic ions is just like the bonding within molecular compounds (Section 5.3), but the group of atoms has either more or fewer electrons than protons and therefore has an overall charge. Compounds that contain polyatomic ions are ionic, and their formulas are written by the same procedure described for binary ionic compounds. The only difference is that the polyatomic ion formula is enclosed in parentheses when more than one such ion is present. For example, the formula of aluminum nitrate is Al(NOg)g. The compounds are also named in the same manner as binary ionic compounds, with the... 

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... 

The formulas of ionic compounds have a different meaning from those of molecular compounds. Each crystal of sodium chloride has a different total number of cations and anions. We cannot simply specify the numbers of ions present as the formula of this ionic compound, because each crystal would have a different formula and the subscripts would be enormous numbers. However, the ratio of the number of cations to the number of anions is the same in all the crystals, and the chemical formula shows this ratio. In sodium chloride, there is one Na+ ion for each Cl ion so its formula is NaCl. Sodium chloride is an example of a binary ionic compound, a compound formed from the ions of two elements. Another binary compound, CaCl2, is formed from Ca2+ and Cl- ions in the ratio 1 2, which is required for electrical neutrality. 

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. 

Write the formula for the binary ionic compound that forms from each pair of elements. (Chapter 8)... 

Write the formula for each of the following binary ionic compounds. 

Binary ionic compound An ionic compound whose formula contains one symbol for a metal and one symbol for a nonmetal. 

A binary Ionic compound is one composed of ions from only two elements, one a metal, the other a nonmetal. NaCl, CaF2, and FeCl3 are all binary ionic compounds. Before starting to develop formulas for ionic compounds, it is necessary to know the monatomic ions (ions formed from a single atom) of the common metals and nonmetals. 

Monatomic ions Binary ionic compounds are composed of positively charged monatomic ions of a metal and negatively charged monatomic ions of a nonmetal. A monatomic ion is a one-atom ion, such as Mg + or Br . Table 7.7 indicates the charges of common monatomic ions according to their location on the periodic table. What is the formula for the beryllium ion The iodide ion The nitride ion ... 

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