OB: Table E, the polyatomic ions, making more ionic compounds!

OB: Table E, the polyatomic ions, making more ionic compounds! Get out your reference tables, open to page 1. Ready, set, go!

We now know about the monoatomic ions of the periodic table and how they bond ionically. We know also about how the funky transitional metals make cations, and how we use roman numerals to give them their stock names. We even know why noble gases don’t bond with anything else, which is kind of strange since all those atoms gain or lose electrons to get isoelectric to noble gases so that they can bond. Table E shows us a whole bunch of POLYATOMIC IONS. Poly means more than one, atomic means atoms stuck together. POLYATOMIC IONS are multiple atoms bonded together in certain ways that act as a single charged particle (positive cations, or negative anions). On table E, these can be +1, +2, -1, -2, or -3. They come as a single bunch, they have special names, you never ever change their names. Most end in –ide, like good anions, but some don’t. Why, because.

Let’s look at Table E now. We’ll start with ammonium. Ammonium is one nitrogen atom bonded with four hydrogen atoms, but they act as a +1 cation (like sodium or lithium). They just come hand cuffed (bonded) together. If sodium bonded to chlorine, it bonds into NaCl, in a 1:1 ratio since the +1 charge balances the -1 charge. There is a transfer of one electron from the cation to the anion, and they end up wildly attracted together, making an ionic bond, forming into an ionic compound. If ammonium bonded to chlorine, it would bond into NH4Cl, also in a 1:1 ratio since the +1 charge balances the -1 charge. There is a transfer of 1 electron from the cation to the anion, and they end up wildly attracted together, making an ionic bond, forming into an ionic compound. Working with the polyatomic ions, remember these rules: Cations still go first, always. Anions still always go second. Never ever change the name of a table E polyatomic ion. NH4+1

We will skip the other positive polyatomic ions for now. Let’s try to bond sodium with the acetate anion: (name then formula) Na+1 and C2H3O2-1 will form ________________________________________ How about potassium with the cyanide ion K+1 and CN-1 will form into _______________________________________ Magnesium will bond with the carbonate ion Mg+2 and CO3-2 will form into ___________________________________

We will skip the other positive polyatomic ions for now. Let’s try to bond sodium with the acetate anion: Na+1 and C2H3O2-1 will form into sodium acetate, written as: NaC2H3O2 How about potassium with the cyanide ion K+1 and CN-1 will form into potassium cyanide, written as KCN Magnesium will bond with the carbonate ion Mg+2 and CO3-2 will form into magnesium carbonate, written as MgCO3

These are really easy, except when the polyatomics have to come in multiples, like these: Magnesium cation + hydroxide ion forms magnesium hydroxide Mg+2 + OH-1 creates a simple problem for us, because of the NOT 1:1 ratio needed to keep things balanced. Remember, electron transfer must be perfect, and the resulting ionic compound must be neutral electrically. What can we do? (when in doubt, don’t think, criss cross) Mg+2 + OH-1 becomes Mg(OH)2 We need two hydroxides to pick up one electron each, to bond with one magnesium cation.

This slide is a break slide. This is a lot of chem, and it’s not easy. Who has a question about Table E? Who has a question about ions in general? Who has a question about transitional metal ions? Who knows the first thing to look at ina compound or formula to tell if the substance is ionic, or is an ionic compound? Ask now, or hold on…

It’s tricky tricky tricky, because you will forget the parenthesis, or put the parenthesis in every where, even like Na(Cl) because you will like them. Practice, patience, and more practice please. Soon you’ll also do Magnesium (II) oxide, but you shouldn’t. Here goes, 4 names and formulas, please. Combine: Lithium + the chromate anion Aluminum + hypochlorite anion Magnesium + thiocyanate anion Calcium + the permanganate anion

Combine: Lithium + the chromate anion form lithium chromate Li+1 + CrO4-2 Li2CrO4 Aluminum + hypochlorite anion form aluminum hypochlorite Al+3 + ClO-1 Al(ClO)3 Magnesium + thiocyanate anion form magnesium thiocyanate Mg+2 + SCN-1 Mg(SCN)2 Calcium + the permanganate anion form calcium permanganate Ca+2 + MnO4-1 Ca(MnO4)2

Try a few more… What is the formula for beryllium phosphate? _____________________ What’s the formula for sodium hydrogen carbonate (bakin’ soda)? _____________ Formula for ammonium nitrate? _____________________ How about ammonium dichromate? _____________________________ Super hard ones coming now: Bismuth (V) thiosulfate ________________________________ Cobalt (III) chlorate ________________________________

Try a few more… What is the formula for beryllium phosphate? Be3(PO4)2 What’s the formula for sodium hydrogen carbonate (bakin’ soda)? NaHCO3 Formula for ammonium nitrate? NH4NO3 How about ammonium dichromate? (NH4)2Cr2O7 Super hard ones coming now: Bismuth (V) thiosulfate ________________________________ Cobalt (III) chlorate ________________________________

Try a few more… What is the formula for beryllium phosphate? Be3(PO4)2 What’s the formula for sodium hydrogen carbonate (bakin’ soda)? NaHCO3 Formula for ammonium nitrate? NH4NO3 How about ammonium dichromate? (NH4)2Cr2O7 Super hard ones coming now: Bismuth (V) thiosulfate Bi2(S2O3)5 Cobalt (III) chlorate Co(ClO3)3

Tonight: Do Naming Compounds HW #4 all about naming Transitional Metal Ionic Compounds. Review 2 of the four drills, look at polyatomic ion handout (coming soon but online now). Today was hard Today was a lot You are a good person Peace, Love, and Chemistry. Don’t get disheartened, you’re not supposed to “get it” all yet. Give it a few days. Read your diary, it’s very special this one.

OB: Table E, the polyatomic ions, making more ionic compounds!