Naming Ions 9.1 and 9.2

Review: cations and anions Ions are formed by the gain or loss of electrons Ions are formed by the gain or loss of electrons Metallic elements tend to LOSE electrons, forming positive ions (cations) Metallic elements tend to LOSE electrons, forming positive ions (cations) Group 1 loses 1 electron ex) Li +, Na +, K +, etc Group 1 loses 1 electron ex) Li +, Na +, K +, etc Group 2 loses 2 electrons ex) Mg +2, Ca +2 Group 2 loses 2 electrons ex) Mg +2, Ca +2 What does group 13 do? What does group 13 do? Non-metals tend to GAIN electrons, forming negative ions (anions) Non-metals tend to GAIN electrons, forming negative ions (anions) Group 16 gains 2 electrons ex) O -2, S -2 Group 16 gains 2 electrons ex) O -2, S -2 Group 17 gains 1 electron ex) F -, Cl - Group 17 gains 1 electron ex) F -, Cl - What does group 15 do? What does group 15 do?

Group 14 elements generally do not form ions Group 14 elements generally do not form ions C and Si are found in Molecular Compounds C and Si are found in Molecular Compounds Group 18 (Noble Gases) do not bond Group 18 (Noble Gases) do not bond Transition Metals (along with Sn and Pb) can have more than one common ionic charge. DANGER ZONE! Transition Metals (along with Sn and Pb) can have more than one common ionic charge. DANGER ZONE! The Stock System The Stock System Include the charge in the name in roman numerals Include the charge in the name in roman numerals Ex. Fe 2+ is called Iron (II) ion Ex. Fe 2+ is called Iron (II) ion Fe 3+ is called Iron (III) ion Fe 3+ is called Iron (III) ion Classical Names Classical Names The root word + the ending –ous for the lower of the 2 ionic charges or –ic for the higher of the two ionic charges The root word + the ending –ous for the lower of the 2 ionic charges or –ic for the higher of the two ionic charges Ex. Iron (ferrum in Latin) Ex. Iron (ferrum in Latin) Fe 2+ is called the ferrous ion Fe 2+ is called the ferrous ion Fe 3+ is called the ferric +ion Fe 3+ is called the ferric +ion -ic > -ous -ic > -ous What about the rest?

Use the name to tell you which cation has the larger or smaller charge You should memorize the ions for copper and iron. You should memorize the ions for copper and iron.

Transition Metal exceptions These only have one charge. They do not require roman numerals. These only have one charge. They do not require roman numerals. Silver = Ag + Silver = Ag + Cadmium = Cd 2+ Cadmium = Cd 2+ Zinc = Zn 2+ Zinc = Zn 2+ Aluminum = Al 3+ Aluminum = Al 3+

Practice Write the symbol with charge. Identify as cation or anion. Write the symbol with charge. Identify as cation or anion. Lead, 4 electrons lost Lead, 4 electrons lost Iodide Iodide Sulfide Sulfide Manganese, 6 electrons lost Manganese, 6 electrons lost

Polyatomic Ions Polyatomic Ions: Tightly bound groups of atoms that behave as a unit and carry a charge “Mutants” of the bonding world. Have covalent (sharing) bonds but… Have covalent (sharing) bonds but… End up w/ more or less electrons that you would expect End up w/ more or less electrons that you would expect Cannot be broken into separate parts Cannot be broken into separate parts

Polyatomic Ions: See Chapter 9 post for which ones you need to memorize…. You have 2o ions to memorize. You need to know the name, symbol, and charge. See Message from Mrs. C announcements for your quiz date.

Polyatomic Naming Info Most names end in –ate or –ite Most names end in –ate or –ite -ite has one less oxygen than –ate -ite has one less oxygen than –ate Sulfite SO 3 2-, Sulfate SO 4 2- Sulfite SO 3 2-, Sulfate SO 4 2- Nitrite NO 2 - vs. Nitrate NO 3 - Nitrite NO 2 - vs. Nitrate NO 3 - SAME CHARGE DIFFERENT OXYGEN COUNT SAME CHARGE DIFFERENT OXYGEN COUNT I got sick from something I ate I got sick from something I ate Ic and ate have the higher charge number and oxygen count respectively. Ic and ate have the higher charge number and oxygen count respectively.

Some don’t end with –ite or -ate Ammonium (NH 4 + ) Ammonium (NH 4 + ) Cyanide (CN - ) Cyanide (CN - ) Hydroxide (OH - ) Hydroxide (OH - ) (Always some pesky exceptions to the rule…) (Always some pesky exceptions to the rule…)

What about the ions with hydrogen? When the formula begins in H (ex. HCO 3 - ) imagine the H is a hydrogen ion (H + ) combined with another polyatomic ion When the formula begins in H (ex. HCO 3 - ) imagine the H is a hydrogen ion (H + ) combined with another polyatomic ion H + + CO 3 2- → HCO 3 - (Hydrogen Carbonate) H + + CO 3 2- → HCO 3 - (Hydrogen Carbonate) Notice how the charges add together to create the final charge of the polyatomic ion Notice how the charges add together to create the final charge of the polyatomic ion Show the formulas for the formation of HPO 4 2- and H 2 PO 4 - from two different ions just like we did above. Show the formulas for the formation of HPO 4 2- and H 2 PO 4 - from two different ions just like we did above. H + + PO 4 3- → HPO 4 2- (Hydrogen Phosphate) H + + PO 4 3- → HPO 4 2- (Hydrogen Phosphate) H + + PO 3 3- → HPO 3 2- (Hydrogen Phosphite) H + + PO 3 3- → HPO 3 2- (Hydrogen Phosphite) H + + H + + PO 4 3- → H 2 PO 4 - (Dihydrogen Phosphate) H + + H + + PO 4 3- → H 2 PO 4 - (Dihydrogen Phosphate)