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Naming Polyatomic ions (P.A. Ions). The Root Ions (on the board) Carbonate CO 3 2- Nitrate NO 3 - Sulfate SO 4 2- Chlorate ClO 3 - Phosphate PO 4 3- Chromate.

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Presentation on theme: "Naming Polyatomic ions (P.A. Ions). The Root Ions (on the board) Carbonate CO 3 2- Nitrate NO 3 - Sulfate SO 4 2- Chlorate ClO 3 - Phosphate PO 4 3- Chromate."— Presentation transcript:

1 Naming Polyatomic ions (P.A. Ions)

2 The Root Ions (on the board) Carbonate CO 3 2- Nitrate NO 3 - Sulfate SO 4 2- Chlorate ClO 3 - Phosphate PO 4 3- Chromate CrO 4 2- Acetate C 2 H 3 O 2 -

3 Common Exceptions Ammonium NH 4 + Hydronium H 3 O + Hydroxide OH - Peroxide O 2 2- Cyanide CN -

4 Rules to Naming P.A. Ions 1.Change the suffix of the root ion from –ate to –ite when you subtract one Oxygen Example: Sulfate = SO 4 2- Subtract 1 Oxygen = SO 3 2- = sulfite

5 Rules to Naming P.A. Ions 2. Change the prefix to hypo- and the suffix to -ite when subtracting one Oxygen from the -ite form. Example: Sulfite = SO 3 2- Subtract 1 oxygen = SO 2 2- hyposulfite

6 Rules to Naming P.A. Ions 3. Change the prefix to per- and the ending to -ate when you add one Oxygen to the root form. Sulfate = SO 4 2- Add one oxygen = SO 5 2- = persulfate

7 More Root PA Ions Bromate BrO 3 - Iodate IO 3 - Manganate MnO 3 -

8 Additional Rules to Naming Change an Oxygen to a Sulfur, add the prefix thio- to the Root ion name – Example: Sulfate = SO 4 2- Thiosulfate = add 1 sulfur and subtract 1 oxygen Thiosulfate = SO S -1 O = S 2 O 3 2-

9 Adding Counter Ions Adding Hydrogen ions (H + ) – Add the word Hydrogen to the prefix Follows the numbering prefix system – Example: Hydrogen Sulfate (Charges are conserved) H + + SO 4 2- = HSO 4 - Dihydrogen Sulfate (Charges are conserved) 2H + + SO 4 2- = H 2 SO 4

10 Adding Counter Ions Lets try another one together – Hydrogen Phosphate H + + PO 4 3- = HPO positive charge + 3 negative charges = 2 negative net charge 1 + (-3) = 2- H + + PO 4 3- = HPO 4 2 -

11 Adding Counter Ions Lets try one more with Hydrogen 2H + + PO 4 3- = H 2 PO positive charges + 3 negative charges equals 1 negative net charge 2 + (-3) = -1 2H + + PO 4 3- = H 2 PO What is the name of this compound?

12 Adding Counter Ions Counter Ions from group 1A, 2A & 3A follow the following rule: – Name of element + name of Polyatomic anion Charges must be conserved Example: Sodium Phosphate Na + + PO 4 3- Na 3 PO 4 Note*- It takes 3 positive charges to conserve 3 negative charges

13 Adding Transition Metals Transition metals can have different oxidation states (levels of electron deficiency) stated as roman numerals – Example: Fe (I), Fe (II), Fe (III) Fe (I) = Fe 1+ Fe (II) = Fe 2+ Fe (III) = Fe 3+

14 Adding Transition Metals Charges must be conserved (ions must add up to zero net charge if not explicitly stated) – Example: Iron (II) Sulfate Fe 2+ + SO 4 2- = Fe 2 (SO4) 2 Subscripts can be reduced Answer = Fe(SO 4 )

15 Adding Transition metals Charge, again, must be conserved – Example: Gold (III) Nitrate – Au 3+ + NO 3 - = ? – It takes three Nitrates to counterbalance one Gold ion – 3 positive charged + 3 x (-1) = 0 – Answer = Au(NO 3 ) 3

16 Acids / Bases Three types of Acids – Lewis Acid – Brǿnstead Acid We will focus on this one – Arrhenius Acid

17 Brǿnstead Acid In a reaction, a molecule that gives a H + ion. – Example: HCl + NaOH NaCl + HOH Common acids – Sulfuric Acid H 2 SO 4 – Phosphoric Acid H 3 PO 4 – Hydrochloric Acid HCl – Nitric Acid HNO 3

18 How to name acids Acid general equation: H n X Where H = Hydrogen n = subscript number X = anion (could be one atom or a P.A. anion) – The key to naming is determining what X is.

19 How to name acids If the anion ending is –ide then you must: 1.Add hydro- to the prefix 2.Change the suffix from –ide to –ic 3.Add the word acid to the end of the word. Example: HCl The anion is Chloride Using the rules, it becomes hydrochloric acid

20 Another Example HF – Using normal naming, it would be Hydrogen Fluoride – Now switch to make it an acid What is the answer? Hydrofluoric acid

21 Naming Acids If the X anion ends in –ate then you must 1.Change the –ate ending to –ic 2.Add the word acid to the end Example: H 2 SO 4 = Dihydrogen Sulfate Answer: Sulfuric acid

22 Naming Acids If the X anion ends in –ite then you must 1.Change the –ite ending to –ous 2.Add the word acid to the end Example: H 2 SO 3 = Dihydrogen Sulfite Answer: Sulfurous acid

23 Bases Three types of bases – Lewis base – Brǿnstead base We will focus on this one – Arrhenius base

24 Brǿnstead base A base that accepts a H + ion Example: HCl + NaOH NaCl + HOH Base in blue Common Bases: 1.Hydroxide (OH - ) 2.Ammonia (NH 3 ) 3.Water H 2 O

25 Naming a base Follows the same rules as naming other ionic compounds Example: Al 3+ + OH - Al(OH) 3 Answer: Aluminum Hydroxide

26 Naming Molecular Compounds These compounds are not ionic, but rather they are covalent Example: – CH 4 – SiF 4 – H 2 O – C 2 H 6 O

27 How to name molecular compounds 1.Determine if a compound is ionic or molecular (based on electronegativity) 2.Start with the first element – Give its alphanumeric number prefix – Give its name 3.Go to the second element – Give its alphanumeric number – Give its name

28 How to name molecular compounds 4. Repeat Step 3 until all atoms are taken into account. 5.On the last atom, add the ending –ide.

29 Prefixes Mono = 1 Di = 2 Tri = 3 Tetra = 4 Penta = 5 Hexa = 6 Hepta = 7 Octa = 8 Nona = 9 Deca = 10 Undeca = 11 Dodeca = 12 Trideca = 13 Tetradeca =14 (we will go up to 19)

30 Examples C 8 H 18 Answer = octacarbon Answer – octacarbon octadecahydride Count the first element Compound has 8 carbon atoms Put the prefix octa- in front of the atom carbon Go to the next atom Compound has 18 Hydrogen atoms Add the prefix octadeca to the word hydrogen Since Hydrogen is the last element in the compound, switch the ending to –ide.

31 More Examples SiS 2 Answer = monosilicon disulfide NO 2 Answer = mononitrogen dioxide

32 Law of Definite Proportions A compound must have the same ratio of atoms in it at all times. – Example: H 2 O – There must be 2 Hydrogen atoms for every 1 oxygen atom.

33 Mass & the law of definite proportions Similarly, the mass of each atom in the compound must also follow the same ratio. – Example: H 2 O – If we have 2 grams of hydrogen, we must always have 16 grams of Oxygen – The ratio is always 1:8 for water

34 Example: You have to test one unknown liquid to see if it is water. You have a sample of water that you know (standard). Is the unknown compound water? HO Known4.0 g32.0 g Unknown2.0 g32.0 g

35 Example (Cont) Set up the ratios: Does 1/8 = 1/16? HO Known4.0 g32.0 g Unknown2.0 g32.0 g Compound 1 (known) Compound 2 (unknown) H4.0 g2.0 g O32.0 g


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