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Naming Polyatomic ions (P.A. Ions)

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Presentation on theme: "Naming Polyatomic ions (P.A. Ions)"— Presentation transcript:

1 Naming Polyatomic ions (P.A. Ions)

2 The Root Ions (on the board)
Carbonate CO32- Nitrate NO3- Sulfate SO42- Chlorate ClO3- Phosphate PO43- Chromate CrO42- Acetate C2H3O2-

3 Common Exceptions Ammonium NH4+ Hydronium H3O+ Hydroxide OH-
Peroxide O22- Cyanide CN-

4 Rules to Naming P.A. Ions Change the suffix of the root ion from –ate to –ite when you subtract one Oxygen Example: Sulfate = SO42- Subtract 1 Oxygen = SO32- = 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 = SO32- Subtract 1 oxygen = SO22- 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 = SO42- Add one oxygen = SO52- = persulfate

7 More Root PA Ions Bromate BrO3- Iodate IO3- Manganate MnO3-

8 Additional Rules to Naming
Change an Oxygen to a Sulfur, add the prefix thio- to the Root ion name Example: Sulfate = SO42- Thiosulfate = add 1 sulfur and subtract 1 oxygen Thiosulfate = SO S -1 O = S2O32-

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+ + SO42- = HSO4- Dihydrogen Sulfate (Charges are conserved) 2H+ + SO42- = H2SO4

10 Adding Counter Ions Lets try another one together Hydrogen Phosphate
H+ + PO43- = HPO4⃝ - 1 positive charge + 3 negative charges = 2 negative net charge 1 + (-3) = 2- H+ + PO43- = HPO42 -

11 Adding Counter Ions Lets try one more with Hydrogen
2H+ + PO43- = H2PO4⃝ - 2 positive charges + 3 negative charges equals 1 negative net charge 2 + (-3) = -1 2H+ + PO43- = H2PO41 - 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 PO43- Na3PO4 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) = Fe1+ Fe (II) = Fe2+ Fe (III) = Fe3+

14 Adding Transition Metals
Charges must be conserved (ions must add up to zero net charge if not explicitly stated) Example: Iron (II) Sulfate Fe2+ + SO42- = Fe2(SO4)2 Subscripts can be reduced Answer = Fe(SO4)

15 Adding Transition metals
Charge, again, must be conserved Example: Gold (III) Nitrate Au3+ + NO3- = ? It takes three Nitrates to counterbalance one Gold ion 3 positive charged + 3 x (-1) = 0 Answer = Au(NO3)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 H2SO4 Phosphoric Acid H3PO4 Hydrochloric Acid HCl Nitric Acid HNO3

18 How to name acids Acid general equation: HnX 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:
Add hydro- to the prefix Change the suffix from –ide to –ic 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
Change the –ate ending to –ic Add the word acid to the end Example: H2SO4 = Dihydrogen Sulfate Answer: Sulfuric acid

22 Naming Acids If the X anion ends in –ite then you must
Change the –ite ending to –ous Add the word acid to the end Example: H2SO3 = 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: Hydroxide (OH-) Ammonia (NH3) Water H2O

25 Naming a base Follows the same rules as naming other ionic compounds
Example: Al3+ + OH-  Al(OH)3 Answer: Aluminum Hydroxide

26 Naming Molecular Compounds
These compounds are not ionic, but rather they are covalent Example: CH4 SiF4 H2O C2H6O

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

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

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

30 Examples C8H18 Answer = octacarbon Answer – octacarbon octadecahydride
Go to the next atom Count the first element Compound has 8 carbon atoms Compound has 18 Hydrogen atoms Add the prefix octadeca to the word hydrogen Put the prefix octa- in front of the atom carbon Since Hydrogen is the last element in the compound, switch the ending to –ide.

31 More Examples SiS2 Answer = monosilicon disulfide NO2
Answer = mononitrogen dioxide

32 Law of Definite Proportions
A compound must have the same ratio of atoms in it at all times. Example: H2O 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: H2O 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? H O Known 4.0 g 32.0 g Unknown 2.0 g

35 Example (Cont) Set up the ratios: Does 1/8 = 1/16? H O Known 4.0 g
Unknown 2.0 g Compound 1 (known) Compound 2 (unknown) H 4.0 g 2.0 g O 32.0 g

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