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22.3 Notes Continued. Objectives. Write formulas and names for ionic compounds. Step By Step – Naming Compounds. 1. Write the name of the positive ion Transition metals - determine the oxidation number of the ion from the formula of the compound.
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Objectives • Write formulas and names for ionic compounds
Step By Step –Naming Compounds 1. Write the name of the positive ion • Transition metals - determine the oxidation number of the ion from the formula of the compound. • Write the charge of the positive ion using roman numerals in parentheses after the ion’s name
Naming Continued 2. Write the root name of the negative ion. The root is the first part of the element’s name from the periodic table 3. Add the ending -ideto the root. The table lists several elements and their -ide counterparts F-1 Fluorine F-1 Fluoride
Name These • Na+1 • Al+3 • Fe+3 • Fe+2 • Li+1 • N-3 • Br-1 • O-2 • Ga+3
Subscripts • Do not become part of the name for ionic compounds • However, subscripts can be used to help determine the charges of these metals that have more than one positive charge (transition metals).
Other Ionic Compounds • Not all compounds are binary. • Baking soda has the formula NaHCO3. • Example of an ionic compound that is not binary • Some compounds, are composed of more than 2 elements
Naming Polyatomic Ions • The name NEVER changes • You do not add or remove any letters • You simply write the name of the polyatomic NH4ClO3 = ammonium chlorate
Example • Name of CuO • Need the charge of Cu • O is -2 • Because 1:1 ratio, Cu must be +2 • Copper (II) oxide
Example • Name CoCl3 • Cl is -1, there are three of them = -3 • Co must be +3 • Cobalt (III) chloride
Examples Write the names of the following • Na3N • CrN • PbO2 • K2Se • Li(CN) • Fe(OH)3 • (NH4)2CO3 • NiPO4
Things to look for • If cations have (), the number is their charge. • If anions end in -ide they are probably off the periodic table • If anion ends in -ate or -ite it is polyatomic
1. Write the symbol of the element (or polyatomic ion) with the positive oxidation number or charge 2. Write the symbol of the element (or polyatomic ion) with the negative oxidation number 3. The charge (without the sign) of one ion becomes the subscript of the other ion. Reduce the subscripts to the smallest whole numbers that retain the ratio of ions. 1. Write the name of the positive ion 2. Check to see if the positive ion is capable of forming more than one oxidation number. 3. Write the root name of the negative ion. The root is the first part of the element’s name 4. Add the ending -ide to the root. If more than 2 elements, you are dealing with a polyatomic Naming Writing Formulas Recap of instructions
In-Class Assignment/Homework • Finish Criss Cross WKT from 2/27 • C2O4 = Oxalate