1. Guide to Naming Ionic Compounds February 18

2. Cations (+) – The name of a cation is the same as the name of the element – Find name either on the periodic table or from memory – A few cations need Roman numerals with the name Naming Ions and Ionic Compounds

3. All d-block elements except Ag +, Zn 2+, Cd 2+ Some p-block elements Cations that need Roman Numerals Zn 2+ Ag + Cd 2+

4. I, II, III, IV, V, VI, VII, IX, X, etc.  Some cations need Roman numerals because they can form more than one ion by losing different numbers of valence electrons The numeral tells you the charge of the ion. For example: – SymbolCation name – Ti 2+ titanium (II) – Ti 4+ titanium (IV) Roman Numerals

5. All d-block elements need Roman numerals except Ag +, Zn 2+, Cd 2+ – Silver, zinc, and cadmium will only form one ion. The charge will always be the same for these three cations. SymbolCation name – Ag + silverNOT: Silver (I) – Zn 2+ zincNOT: Zinc (II) – Cd 2+ cadmiumNOT: Cadmium (II) Exceptions

6. Cation nameSymbol – SodiumNa + – HydrogenH + – Vanadium (III)V 3+ – Tin (II)Sn 2+ Examples: Name to Symbol All cations have positive charges The Roman numeral tells us the charge of the vanadium and tin ions We know the charge of the sodium and hydrogen cations by looking at a periodic table

7. Depends on number of valence electrons How many electrons does the atom need to gain or loose to reach a full valence shell? – Will loose to reach 0 electrons or – Will gain to reach 8 electrons – If it looses electrons, the ion is positive – If it gains electrons, the ion is negative Note on Determining the Charge

8. Another way to think about ionic charge…

9. SymbolCation name – Sr 2+ Strontium – Cd 2+ Cadmium – Cu 2+ Copper (II) – Pb 3+ Lead (III) – Pb 2+ Lead (II) – K + Potassium Examples: Symbol to Name Sr 2+ and K + do not need Roman numerals because they are in the s-block The charge of the ion symbol tells us what Roman numeral to write in the name. Copper and lead need Roman numerals because they are found in the d-block and lower-left p-block and form more than one ion. Cadmium does not need a Roman numeral because it is one of the three d- block exceptions

10. Anions (-) – The name of a anion is similar to the name of the element Find name either the periodic table or from memory Drop the ending of the element name Add –ide to the stem – NOTE: If the anion’s name ends in –ide and is NOT cyanide (CN - ), hydroxide (OH - ), or peroxide (O 2 2- ), it will be an ion of an element you find on the periodic table Naming Ions and Ionic Compounds

11. Cation nameSymbol – BromideBr - – OxideO 2- – NitrideN 3- Examples: Name to Symbol All anions have negative charges All the names end in –ide: -Bromine  bromide -Oxygen  Oxide -Nitrogen  Nitride We know the charge of the anions by looking at a periodic table

12. Another way to think about ionic charge…

13. Symbol Element name Anion name – S 2- sulfur Sulfide – Cl - chlorine Chloride – P 3- phosphorous Phosphide Examples: Symbol to Name

14. Polyatomic Ions A molecule with a charge You will need to memorize the names They behave just like monotomic cations and anions

16. Ion nameFormula – OxalateC 2 O 4 2- – ChlorateClO 3 - – AcetateCH 3 COO - – AmmoniumNH 4 + Examples: Name to Formula

17. Ion nameFormula – O 2 2- Peroxide – CH 3 COO - Acetate – Cr 2 O 7 2- Dichromate – AsO 4 3- Arsenate – MnO 4 - Permanganate Examples: Formula to Name

18. Look for clues in the polyatomic ion names Example:  Cr 2 O 7 2- Dichromate Helpful Tip 1: Hints in names -Chromate sounds like chromium -Di means two -Dichromate has two chromiums in it

19. If two similar ions have names that end in –ate and –ite, -ate will have more oxygen – ClO 3 - Chlorate 3 oxygens – ClO 2 - Chlorite2 oxygens – NO 3 - Nitrate 3 oxygens – NO 2 - Nitrite2 oxygens – SO 4 2- Sulfate 4 oxygens – SO 3 2- Sulfite3 oxygens Helpful Tip 2: -ate vs. –ite

20. Per-: 1 more oxygen, same charge Hypo-: 1 less oxygen, same charge – ClO 4 - Perchlorate4 oxygens – ClO 3 - Chlorate 3 oxygens – ClO 2 - Chlorite2 oxygens – ClO - Hypochlorite1 oxygen Helpful Tip 3: Per- and Hypo-