Binary compounds of two nonmetals

In general, binary compounds of two nonmetals are molecular, whereas binary compounds formed by a metal and a nonmetal are ionic. Water (H20) is an example of a binary molecular compound, and sodium chloride (NaCl) is an example of a binary ionic compound. As we shall see, these two types of compounds have... 

Nitrogen trichloride. Although this is a binary compound of two nonmetals, it can be named with Roman numeral designations. It is indeed possible to call this nitrogen(III) chloride in the most modern usage, but most chemists do not do that yet. 

Binary compounds of two nonmetals are covalently bonded. However, strong acids in water form ions completely. 

CUCI2 and Ca(H2P04)2 are ionic compounds. To name these compounds, we must identify and name the ions. CIO2 and HIO4 are molecular compounds. CIO2 is a binary compound of two nonmetals, and HIO4 is an oxoacid. 

The first compounds to be discussed will be compounds of two nonmetals. These binary compounds are named with the element to the left or below in the periodic table named first. The other element is then named, with its ending changed to -ide and a prefix added to denote the number of atoms of that element present. If one of the elements is to the left and the other below, the one to the left is named first unless that element is oxygen or fluorine, in which case it is named last. The same order of elements is used in writing formulas for these compounds. (The element with the lower electronegativity is usually named first refer to Table 5-1.) The prefixes are presented in Table 6-2. The first six prefixes are the most important to memorize. 

Most binary compounds (compounds of two elements) of metals and nonmetals arc essentially ionic. All compounds involving only nonmetals are essentially covalent except for compounds containing the NH4 ion. 

Ionic compounds consist of positive ions (cations) and negative ions (anions) hence, ionic compounds often consist of a metal and nonmetal. The electrostatic attraction between a cation and anion results in an ionic bond that results in compound formation. Binary ionic compounds form from two elements. Sodium chloride (NaCl) and sodium fluoride (NaF) are examples of binary ionic compounds. Three elements can form ternary ionic compounds. Ternary compounds result when polyatomic ions such as carbonate (C032 ), hydroxide (OH-), ammonium (NH4+), form compounds. For example, a calcium ion, Ca2+, combines with the carbonate ion to form the ternary ionic compound calcium carbonate, CaC03. Molecular compounds form discrete molecular units and often consist of a combination of two nonmetals. Compounds such as water (H20), carbon dioxide (C02), and nitric oxide (NO) represent simple binary molecular compounds. Ternary molecular compounds contain three elements. Glucose ( 12 ) is a ternary molecular compound. There are several distinct differences between ionic and molecular compounds, as summarized in Table 1.2. 

Although the general term carbide applies to the binary compounds of the element carbon, this term is used in systematic nomenclature only when carbon is the more electronegative of the two elements involved. Thus, C02 is called carbon dioxide and not oxygen carbide since oxygen is more electronegative than carbon. Although carbon forms binary compounds with most of the nonmetals, metalloids, and metals, only a few of the more common members of this class are considered here. 

Using Figure 5.4, determine the formulas of two binary compounds of nonmetals that have only nonpolar bonds and thus only van der Waals forces and lack of total symmetry. 

The preceding method is sufficient for naming binary ionic compounds containing metals that exhibit only one oxidation number other than zero (Section 4-4). Most transition metals and the metals of Groups IIIA (except Al), IVA, and VA, exhibit more than one oxidation number. These metals may form two or more binary compounds with the same nonmetal. Ta distinguish among all the possibilities, the oxidation number of the metal is indicated by a Roman numeral in parentheses following its name. This method can be applied to any binary compound of a metal and a nonmetal. 

Nearly all binary molecular compounds involve two nonmetals bonded together. Although many nonmetals can exhibit different oxidation numbers, their oxidation numbers are not properly indicated by Roman numerals or suffixes. Instead, elemental proportions in binary covalent compounds are indicated by using a prefix system for both elements. The Greek and Latin prefixes for one through ten are mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca. The prefix mono- is omitted for both elements except in the common name for CO, carbon monoxide. We use the minimum number of prefixes needed to name a compound unambiguously. The final a in a prefix is omitted when the nonmetal stem begins with the letter o we write heptoxide, not heptaoxide. ... 

Start with a binary molecular compound. Note that a binary molecular compound is composed only of two nonmetal atoms—not metal atoms or ions. An example is dinitrogen monoxide (N2O), a gaseous anesthetic that is more commonly known as nitrous oxide or laughing gas. The naming of nitrous oxide is explained in the following rules. 

A binary chemical compound contains only two elements the major types are ionic (compounds of a metal and a non-metal) and nonionic or molecular (compounds between two nonmetals). Answers depend on student responses, cation (positive ion)... 

A binary compound is a compound composed of only two elements. Binary compounds composed of a metal and a nonmetal are usually ionic and are named as ionic compounds, as we have just discussed. (For example, NaCl, MgBr2, and AI2N3 are all binary ionic compounds.) Binary compounds composed of two nonmetals or metalloids are usually molecular and are named using a prefix system. Examples of binary molecular compounds are H2O, NH3, and CCI4. Using this prefix system, you name the two elements using the order given by the formula of the compound. 

Binary compounds are those formed between two elements. If one of the elements is a metal and the other a nonmetal, the binary compoimd is usually made up of ions that is, it is a binary ionic compound. To name a binary compound of a metal and a nonmetal,... 

If the two elements in a binary compound are both nonmetals instead of a metal and a nonmetal, the compound is a molecular compoimd. The method of naming these compounds is similar to that just discussed. For example,... 

When two nonmetals combine with each other, the product is most often a binary molecular compound. There is no simple way to deduce the formulas of such compounds. There is, however, a systematic way of naming molecular compounds that differs considerably from that used with ionic compounds. 

The systematic name of a binary molecular compound, which contains two different nonmetals, consists of two words. 

We can often decide whether a substance is an ionic compound or a molecular compound by examining its formula. Binary molecular compounds are typically formed from two nonmetals (such as hydrogen and oxygen, the elements in water). Ionic compounds are typically formed from the combination of a metallic element with nonmetallic elements (such as the combination of potassium with sulfur and oxygen to form potassium sulfate, K2S04). Ionic compounds typically contain one metallic element the principal exceptions are compounds containing the ammonium ion, such as ammonium nitrate, which are ionic even though all the elements present are nonmetallic. 

Some compounds, namely molecular compounds, contain only nonmetals. Normally the compounds you need to name are binary compounds (containing only two elements). If you have highlighted the metalloids on your periodic table, everything to the right of the metalloids is a nonmetal. The following rules apply to both nonmetals and metalloids. The only nonmetal excluded from these nomenclature rules is hydrogen. 

Many hydrogen compounds are acids. Acids require a different system of nomenclature than other compounds. There are two types of acids binary acids and ternary acids. All acids include the word acid in their name. Binary acids contain only two elements one of which is hydrogen and the other a nonmetal. When naming binary acids, the prefix hydro- appears before the root name of the nonmetal, and there will be an -ic suffix. As an acid, H2S would be hydrosulfuric acid. We used H2S to illustrate the fact that there can be two possible names, hydrogen sulfide or hydrosulfuric acid. If your instructor does not specify which name to use, either is correct. Technically, the name hydrosulfuric acid only applies to aqueous solutions of H2S, H2S(aq). 

Binary compounds are compounds that consist of only two elements. Some binary compounds have special names, and these special names supersede any of the rules given below. H20 is water, NH3 is ammonia, and CH4 is methane. All other binary compounds have a name with a suffix ide. Binary compounds may be subdivided into metal type, nonmetal type, and acid type. 

The chemical properties of selenium fall between sulfur and tellurium. Thus, selenium reacts with oxygen similarly to sulfur, forming two oxides, selenium dioxide, Se02 and trioxide, SeOs. The metal combines with halogens forming their halides. With nonmetals, selenium forms binary compounds exhibiting oxidation states +4 and -i-6. 

The rules for naming binary compounds are summarized in Fig. 2.22. Notice that prefixes to indicate the number of atoms are used only in Type III binary compounds (those containing two nonmetals). An overall strategy for naming compounds is summarized in Fig. 2.23. 

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