Naming Covalent Compounds

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Naming Covalent Compounds, Acids, and Bases

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Covalent Compounds Share

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Covalent Compounds  Unlike ionic compounds who transfer its electron from one element to another, covalent compounds share their electrons.

 Covalent compounds can easily be identified because they are made with two non-metals.

 Therefore, if there aren’t any metals in the compounds it must be a covalent compound.

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Covalent Compounds  Covalent compounds do not have ions; therefore, the do not carry charges.

 Instead the elements share the electrons, forming bonds.

 The electronegativity of each element also plays a big part on the bonding.

 There are two types of covalent compounds: polar, and non-polar.

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Polarity in Bonds  Polarity is determined by the electronegativity of the elements in a compound.

 If the difference in the electronegativity of two elements in less than 0.5, then it is non-polar.

 If the difference in the electronegativity is between 0.51.7, then it is polar.

 Anything greater than that would be considered ionic.

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Electronegativity Chart

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Covalent Compounds  Unlike ionic compounds, the ratio between how many of one element will combine with another is not always fixed.

 For example, in an ionic compound when you mix Na and Cl you will get NaCl, never will it be different.

 In a covalent compound, however, you may mix C and O and get CO or CO2.

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How to Name Covalent Compounds  In order to distinguish between compounds such as CO and CO2 prefixes needs to be used to distinguish the ratio between the two elements.

 The prefixes that used are:

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Examples  The first element’s name doesn’t change, unless you need to use a prefix to inform that there are more than one of that element.

 You still need to add –ide at the end of the last element.  CO would be named carbon monoxide.  CO2 would be named carbon dioxide.  N2O would be named dinitrogen monoxide.

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Practice Problems:  Name the following compounds:  N2O5  BrF5  SiCl4  N2O3  NO  H2O

 Answers:  Dinitrogen pentoxide  Bromine pentafloride

 Dinitrogen trioxide  Nitrogen monoxide  Water

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Acids and Bases  Acids are aqueous solutions that donates a proton, H+, when mixed with other compounds or solutions.

 Bases are aqueous solution that accepts a proton, H+, when mixed with other compounds or solution.

 When you mix an acid and a base water is formed, because bases have an OH- that accepts the H+ from the acid and form H2O.

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Acids  There are two types of acids: binary acids and ternary/terciary acids.

 As the names suggests binary acids are acids that contain two elements. One of which is hydrogen.

 Ternary acids have more than two elements. Usually a mixture of hydrogen and a polyatomic ion.

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Binary Acids  Binary acids always have he prefix hydro- in front of the name.

 Acids must always be in aqueous form, if it is in solid form than it is named as a regular compound.

 The second element’s ending is charged to –ic when naming the acid.

 The word acid must follow the name of the compound.  For example: HBr(aq) will be named hydrobromic acid.

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Naming Binary Acids

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Terciary Acids  When naming an acid that contains a polyatomic ion in it you do not add the prefix hydro-.

 HINT: Whenever you see the word HYDRO you must have a binary acid.

 If the polyatomic ion’s ending is –ate it then becomes – ic.

 If the polyatomic ion’s ending is –ite then it becomes – ous.

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Naming Ternary Acids

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Group 7 Ternary Acid  Notice how in the previous chart some of them had prefixes.

 Chlorine, bromine, and iodine can combine with up to 4 oxygens to form a polyatomic ion.

 In order to distinguish between the four ions we need to add prefixes.

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Group 7 Ternary Acid

 The two with the highest number of oxygen ClO3- and ClO4- carry the ending –ate, but the one with the highest of all carry the prefix per-.

 Therefore, ClO4- is named perchlorate and ClO3- is named chlorate.

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Group 7 Ternary Acid

 Likewise, the two with the lowest number of oxygen ClO2- and ClO- carry the ending –ite, but the one with the least oxygen carry the prefix hypo-.

 Therefore, ClO2- is named chlorite and ClO- is named hypochlorite.

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Naming Ternary Acid Containing Group 7 Polyatomic Compounds

 Other than including the prefixes, naming these compound when they are mixed with hydrogen in aqueous form is the same as any other ternary acid.

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