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Unit 5 “Chemical Names and Formulas” Chemistry Troy High School Mr. Blake H2OH2O.

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Presentation on theme: "Unit 5 “Chemical Names and Formulas” Chemistry Troy High School Mr. Blake H2OH2O."— Presentation transcript:

1 Unit 5 “Chemical Names and Formulas” Chemistry Troy High School Mr. Blake H2OH2O

2 Section 9.1 Naming Ions

3 Atoms and Ions are electrically neutral. –Same number of p+ and e- - atoms with a charge (+ or -) Made by gaining or losing. –Only electrons can move

4 An Anion is… A negative ion = electrons. Nonmetals gain electrons. Charge is written as a superscript on the right. F 1- Has gained electron (-ide is new ending = ) O 2- Gained electrons ()

5 A Cation is… A positive ion = electrons. lose electrons K 1+ Has lost electron (no name change for positive ions) Ca 2+ Has lost electrons

6 Predicting Ionic Charges Group 1A: Lose electron to form ions H 1+ Li 1+ Na 1+ K 1+ Rb 1+

7 Predicting Ionic Charges Group 2A: Loses electrons to form ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

8 Predicting Ionic Charges Group 3A: Loses electrons to form Loses electrons to form ions ions B 3+ Al 3+ Ga 3+

9 Predicting Ionic Charges Group 4A: Do they lose 4 electrons or gain 4 electrons? ! Group 4A elements rarely form ions (they tend to share) ! Group 4A elements rarely form ions (they tend to share)

10 Predicting Ionic Charges Group 5A: Gains _ Gains _ electrons to form ions ions N 3- P 3- As 3- Nitride Phosphide Arsenide

11 Predicting Ionic Charges Group 6A: Gains electrons to form ions Gains electrons to form ions O 2- S 2- Se 2- Oxide Sulfide Selenide

12 Predicting Ionic Charges Group 7A: Gains _ electron to form ions Gains _ electron to form ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

13 Predicting Ionic Charges Group 8A: Stable noble gases form ions!

14 Predicting Ionic Charges Group B elements: Many transition elements have possible charge. have possible charge. Iron (II) = Iron (III) = Use of Roman numerals to show charges

15 Naming Cations system – use roman numerals in parenthesis to indicate the charge value

16 Naming cations

17 Predicting Ionic Charges Some elements also Some elements also have more than one possible charge. have more than one possible charge. Tin (II) = Lead ( ) = Pb 2+ Tin (IV) = Lead ( ) = Pb 4+

18 Predicting Ionic Charges Group elements: Some transition elements Some transition elements have only one possible oxidation state, such as these three: have only one possible oxidation state, such as these three: Zinc =Silver =Cadmium = **Do not use roman numerals for these

19 Practice by naming these: Na + Ca 2+ Al 3+ Fe 3+ Fe 2+ Pb 2+ Li +

20 Write symbols for these: Potassium ion Magnesium ion Copper (II) ion Chromium (IV) ion Barium ion Mercury (II) ion

21 Naming Anions Anions are the same charge Change the ending to _ F 1- a Fluorine atom will become a ion.

22 Practice by naming these: Cl - N 3- Br - O 2- Ga 3+

23 Write symbols for these: Sulfide ion Iodide ion Phosphide ion Strontium ion

24 Polyatomic ions are… Groups of atoms that together, have an charge, and one name. Usually end in – or - _ Acetate: C 2 H 3 O 2 - Nitr : NO 3 - Nitr : NO 2 - Permanganate: MnO 4 - Hydroxide: OH - and Cyanide: CN - ?

25 Sulf : SO 4 2- Sulf : SO 3 2- Carbonate: CO 3 2- Chromate: CrO 4 2- Dichromate: Cr 2 O 7 2- Phosph : PO 4 3- Phosph : PO 3 3- Ammonium: NH 4 1+ Know Table 9.3 on page 257 (One of the few positive polyatomic ions)

26 H + Polyatomic ion =…. If the polyatomic ion begins with H, then put “hydrogen” in front of the polyatomic ion: H 1+ + CO 3 2- → HCO 3 1- hydrogen + carbonate → hydrogen carbonate ion H SO 3 HPO 4 HCO 3

27 Helpful Hints on Oxy-Anions 1. _________:smaller # of oxygen 2. _________:larger # of oxygen Ex. NO 3 - ____________________________ NO 2 - ____________________________ SO 4 2- ____________________________ SO 3 2- ____________________________

28 A Guide to Determine Whether the –ate Formula is –XO 3 or –XO 4 : BCN Cl Br I Si P S As Se Transition Metals

29 Section 9.2 Naming and Writing Formulas for Ionic Compounds

30 Writing Ionic Compound Formulas Example: Iron (III) chloride 1. Write the cation and anion with CHARGES! 2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.

31 Writing Ionic Compound Formulas Example: Aluminum sulfide 1. Write the cation and anion with CHARGES! 2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.

32 Writing Ionic Compound Formulas Example: Zinc hydroxide 1. Write the cation and anion with CHARGES! 2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.

33 Writing Ionic Compound Formulas Example: Magnesium carbonate (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Mg 2+ CO Check to see if charges are balanced. They are balanced!

34 Writing Ionic Compound Formulas Example: Barium nitrate (note the 2 word name) 1. Write the cation and anion with CHARGES! 2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.

35 Writing Ionic Compound Formulas Example: Ammonium sulfate 1. Write the cation and anion with CHARGES! 2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.

36 Writing Ionic Compound Formulas Example: Aluminum phosphate 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ PO Check to see if charges are balanced. They ARE balanced!

37 Naming Ionic Compounds 1. Cation, then anion 2. Monatomic cation = name of the element Ca 2+ = ion 3. Monatomic anion = root + -ide Cl - = CaCl 2 =

38 Naming Ionic Compounds If the metal can have more than one charge (), use a Roman numeral in their name: PbCl 2  use the to find the charge on the cation (chloride is always 1-) (Metals with multiple oxidation states) is the lead ( ) cation PbCl 2 = lead ( ) chloride

39 Things to look for: 1) If cations have ( ), the number in parenthesis is their. 2) If anions end in –ide, they are probably off the periodic table () 3) If anion ends in -ate or –ite, then it is

40 Practice by writing the formula or name as required… Iron (II) Phosphate Stannous Fluoride Potassium Sulfide Ammonium Chromate MgSO 4 FeCl 3

41 Section 9.3 Naming and Writing Formulas for Molecular Compounds

42 Molecular compounds are… Made of only Smallest part is a Can’t use charges to figure out how many of each atom (there are no charges present / they share electrons)

43 Molecular compounds are easier! compounds use to determine how many of each. Figure out charges and criss-cross numbers. Molecular compounds: the name tells you the number of atoms. Uses to tell you the exact number of each element present!

44 Prefixes (Table 9.4, p.269) 1 = mono- 2 = di- 3 = 4 = tetra- 5 = 6 = hexa- 7 = hepta- 8 = octa- 9 = nona- 10 =

45 Prefixes To write the name, include: One exception is we don’t write if there is only of the element. Normally, we do not have double vowels when writing names (oa oo ) Prefix + name -ide

46 Practice by naming these: N 2 O NO 2 Cl 2 O 7 CBr 4 CO 2 BaCl 2

47 Write formulas for these: diphosphorus pentoxide tetraiodine nonoxide sulfur hexafluoride nitrogen trioxide carbon tetrahydride phosphorus trifluoride aluminum chloride (Ionic compound)

48 Section 9.4 Naming and Writing Formulas for Acids and Bases

49 Acids are… Compounds that give off ions (H + ) when dissolved in water (the Arrhenius definition) Formula starts with. Always be some Hydrogen next to an. determines the name.

50 Rules for Naming acids: Name it as a normal compound first If the anion attached to hydrogen ends in -ide, put the prefix and change -ide to -acid In other words, if it’s just Hydrogen and one other nonmetal HCl = H 2 S = acid

51 Naming Acids If the anion has oxygen in it, then it ends in -ate or -ite 2)Change -ate to -ic acid (use no prefix) Example: HNO 3 Hydrogen + nitrate = 3)Change -ite to -ous acid (use no prefix) Example: HNO 2 Hydrogen + nitrite =

52 Naming Acids Normal ending ____-ide ____-ate ____-ite Acid name is… hydro-___-ic acid _____-ic acid _____-ous acid

53 Practice by naming these: HF H 3 P H 2 SO 4 H 2 SO 3 HCN H 3 PO 4

54 Writing Acid Formulas – in reverse! Hydrogen will be listed first The name will tell you the Be sure the charges cancel out. Starts with hydro? Anion is, ends in –ide No hydro? 1) -ate anion comes from – ending 2) -ite anion comes from – ending

55 Write formulas for these: hydroiodic acid chloric acid carbonic acid phosphorous acid hydrobromic acid

56 Names and Formulas for Bases Base - an ionic compound that produces ions () when dissolved in water (the Arrhenius definition) Named the same way as other ionic compounds: –Name of cation ( ) followed by name of anion (which will be ).

57 Names and Formulas for Bases NaOH = Ca(OH) 2 = To write the formula: 1)Write symbol for metal cation 2)Followed by hydroxide ion (OH 1- ) 3)Use criss-cross method to balance the charges.

58 Practice by writing the formula for the following: Magnesium hydroxide Iron (III) hydroxide Zinc hydroxide

59 Section 9.5 The Laws Governing Formulas and Names

60 Some Laws: Law of Proportions- in a sample of a chemical compound, the of the are always in the proportions. In every molecule of H 2 O (water), the mass ratio of H:O is 1:8

61 Some Laws: Law of Proportions- Whenever two elements form than one compound, the masses of one element that combine with the mass of the other element are in the ratio of small. H 2 O (water) and H 2 O 2 (hydrogen peroxide) 2:1 2:2 2g:16g 2g:32g

62 https://www.youtube.com/watch?v=0OOcp iTiXzMhttps://www.youtube.com/watch?v=0OOcp iTiXzM Law of Definite Proportions - Law of Multiple Proportions by Brightstorm

63 Summary of Naming and Formula Writing For naming, follow the flowchart- Figure 9.20, page 277 For writing formulas, follow the flowchart from Figure 9.22, page 278

64 Helpful to remember In ionic compounds, the net charge is _ (criss-cross method) 2. Put -ide at the end of monatomic 3. An -ite or -ate ending means there is a ion that has 4. Prefixes generally mean ; they show the number of each atom

65 Helpful to remember A Roman numeral after the name of a cation is the of the cation


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