Ternary compounds are composed ofthree various elements. The many common varieties of ternary compoundsconsist that a metallic cation (positive ion) and a polyatomic anion (negativeion). The only common polyatomic ion with a confident charge is theammonium ion. At any rate, to write these formulas you will desire to havereference tables .

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Example 1. Create the properchemical formula because that potassium hydroxide.

Step one - compose the symbols forthe monatomic and polyatomic ion in the compound. Friend will discover thesymbol potassium on table 1 (the routine table). Hydroxide is apolyatomic ion, which will be found on table 2 (polyatomic Chart).Eventually you will acknowledge the surname of a polyatomic ion, but for now if youcan"t discover an ion ~ above one table, look on the other.

Potassium= K Hydroxide = OH

Step two- Look up the oxidation number of the ions connected (in table 5-2b and also 5-2d, orsome comparable tables), and write them together superscripts come the right of theelemental symbols.

Potassium= K+ Hydroxide = OH-

Stepthree - usage the correct mix of ion to create a compound v a netcharge that zero. Parenthesismust be used if girlfriend need more than among a polyatomic ion.In this case, (+1) + (-1) = 0. So, onlyone of every ion is used. No subscripts are necessary. If you neededmore than one hydroxide ion, it would certainly be placed in parenthesis through the subscripton the outside.

KOH

Notethe prominence of upper and also lower case

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - -

Example 2.Show the exactly formula because that Calcium Nitrate.

Step one- create the symbols for the monatomic and also polyatomic ion in the compound.

Calcium= Ca Nitrate = NO3

Step two- Look up the oxidation number of the ions connected (in table 5-2b and also 5-2d, orsome comparable tables), and write them as superscripts come the right of theelemental symbols.

Calcium= Ca2+ Nitrate = NO3-

Stepthree - usage the correct combination of ions to create a compound with a netcharge that zero. Parenthesismust be provided if girlfriend need much more than among a polyatomic ion. Inthis case (+2) + 2(-1) = 0. We need to display two nitrate ion in ourformula. The subscript is placed on the external of the parenthesis to showthat the whole polyatomic ion is doubled.

Ca(NO3)2

Thecorrect usage of parenthesis will seem hard at first, but you must master thisskill v practice!

TheStock System

Someelements, favor iron and lead, have an ext than one oxidation number. If youwere given a compound name favor lead chloride, you would certainly not know if friend shouldused one oxidation number of +2 or +4 for the lead. The stock system isused come specify which type of an element, that reflects multiple oxidation numbers,is used in a certain compound. A roman numeral is shown after thename of the positive ion (cation) to show the oxidation number of thepositive ion.

Example 1.Show the exactly formula for lead (IV) nitrate.

Step one- create the icons for the ions in the compound.

Lead= Pb Nitrate = NO3

Step two- Look up the oxidation number of the an unfavorable ion involved (in table 5-2b and5-2d, or some comparable tables). The optimistic ion will have a positiveoxidation number same to the roman inn numeral. Create the number assuperscripts come the appropriate of the element symbols.

Lead= Pb4+ Nitrate= NO3-

Stepthree - usage the correct mix of ion to create a compound v a netcharge of zero. Parenthesismust be used if you need much more than one of a polyatomic ion.

Pb(NO3)4

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - -

Example 2.Show the exactly formula for Copper (II) Fluoride

Step one- write the signs for the ions in the compound.

Copper= Cu Fluoride = F

Step two- Look increase the oxidation variety of the an unfavorable ion connected (in table 5-2b and5-2d, or some comparable tables). The optimistic ion will have actually a positiveoxidation number equal to the roman numeral. Compose the number assuperscripts come the best of the elemental symbols.

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Copper= Cu2+ Fluoride = F-

Stepthree - usage the correct combination of ions to produce a compound v a netcharge of zero. Parenthesismust be supplied if you need an ext than among a polyatomic ion.