A quick and easy guide to naming and writing them MULTIVALENT IONS

 Multivalent: multi (more than one) + valent (number of valence electrons)  Basically, some metals can form more than one ion. Which ion they form depends on what chemical reaction takes place  This is possible because at the heavier, more massive atomic level, the energy shells are 3-dimensional, so you can have different number of valence electrons interacting with other atoms WHAT ARE MULTIVALENT IONS?

 Look at the Periodic Table in your text book… notice the transition metals have two different ionic charges?  The transition metals do!  There are only a few multivalent ions you will see regularly… here are some examples:  Iron (Fe) 3+ or 2+  Lead (Pb) 2+ or 4+  Nickel (Ni) 2+ or 3+  Copper (Cu) 2+ or1+  Gold (Au) 3+ or 1+ FIND THEM ON THE PT

 When you are writing the name of an ionic compound, you will need to distinguish between which ion of that element you are using. Roman  Numerals are used when indicating an ion’s charge. DISTINGUISHING CHARGES ChargeRoman Numeral +1I +2II +3III +4IV +5V +6VI +7VII

Examples:  Fe 3+  iron (III)  Cu 1+  copper (I) EXAMPLES OF MULTIVALENT CHARGES

Example: Au 3 N 1.Figure out what the metal is (Au) 2.Look at the PT… what are the possible charges? (+1 or +3) 3.Figure out what the non-metal is (N -3 ) 4.Look at the formula… how many ions of each do you have? (3 Au and 1 N) 5.Figure out what charge you would have to use so that the totals would balance out (if you used Au+3 and had 3 of them, the total charge would be +9) (if you used Au+1 and had 3 of them, the total charge would be +3) (since there is only one N, and it has a -3 charge, you would need to use Au +1 to make the charges balance out) 6.Figure out which roman numeral to use for the charge (I) 7.Write the compound name (gold (I) nitride) NAMING MULTIVALENT IONS

Example: PdS 2 1.Identify the metal 2.Look on the PT to list it’s possible charges 3.Identify the non-metal and it’s charge 4.Notice how many ions of each you have 5.Figure out what charge needs to be used so that the positive and negative charges balance out 6.Determine which roman numeral to use for the metal charge 7.Write the compound name * Remember to still add the suffix “ide” to the non- metal PRACTICE NAMING

Example: manganese (IV) sulfide 1.Figure out what these two ions are and write down their charges a.Manganese (IV) = Mn +4 b.S = S -2 2.Determine how many of each ion you need to balance out the charges a.Mn +4 = +4 b.S -2 = - 2You will need another ion of S to balance 3.Note the ratio of positive ions to negative ions a.1 Mn b.2 S 4.Write the formula, indicating the number of each ion in a subscript right after if a.MnS 2 WRITING FORMULAS

Example: colbalt (III) oxide 1.Figure out what the two ions are and write down their charges 2.Determine how many of each ion you need to balance out their charges 3.Note the ratio of positive ions to negative ions 4.Write out the formula, indicating the number of each ion in a subscript right after it PRACTICE WRITING THE FORMULA

 The assignment is to be done individually. If you need help, please ask the peer tutor, TA or myself  This is due on Monday, and is for marks!!  Every day late is -1 mark  Total is out of… ASSIGNMENT #1