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Elements  compounds New properties are created Why do elements form compounds?

Elements  compounds New properties are created Why do elements form compounds? To become more chemically stable by getting a complete outer energy level and lowering potential energy. What are chemical formulas?

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Elements  compounds New properties are created Why do elements form compounds?

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  1. Elements  compounds • New properties are created • Why do elements form compounds? • To become more chemically stable by getting a complete outer energy level and lowering potential energy.

  2. What are chemical formulas? • A formula that tells you number of atoms each element in a compound represented by symbols and subscripts

  3. Subscripts • small numbers to the lower right of the chemical symbol • Represents the number of atoms of that element present in the compound • ***the subscript of 1 is never written in a chemical formula; it is understood since the chemical symbol is there****

  4. Looking at the following formulas state the number of atoms for each compound. • NH4OH • NH4C • Ag2O • 2 K2SO4 • Ca (NO3)2 • 3 Na2S • 2 Al2(SO4)3

  5. Remember • Between metals and nonmetals • Cations and anions • Transferring electrons • Between nonmetals and nonmetals • Sharing electrons Ionic compounds Covalent Compounds

  6. What are characteristics of monatomic ions? • Ions formed from a single atom • Cations and anions • What are binary ionic compounds? • Compounds composed of two elements • Total number of positive and negative charges must be equal

  7. What are characteristics of polyatomic ions? • Form ternary compounds (3 elements) • Covalent molecules with a charge • Behave as if they were one atomic ion

  8. What are common polyatomic ions? • Carbonate – CO32- • Bicarbonate – HCO3- • Phosphate - PO4 3- • Chlorate – ClO3- • Chlorite – ClO2- • Cyanide – CN- • Acetate – C2H3O2- • Ammonium – NH41+ (only positive one) • Hydroxide – OH1- • Nitrite – NO2 1- • Nitrate – NO3 1- • Sulfite – SO3 2- • Sulfate – SO4 2-

  9. Remember, oxidation numbers tell how many electrons an atom has gained, lost, or shared to become stable. • Shown as superscripts. • Main group elements the oxidation number is set. The transition elements and those of group 14 vary.

  10. We use oxidation numbers and their least common multiples to write formulas So, if both subscripts are divisible by the same number, they must be reduced to have formula in proper form. • When writing formulas, the compound should be neutral (same number of + and - charges)

  11. Terms to Know • Type I compounds – ionic compounds made from main group 1, 2, 13 metals and nonmetals of groups 15, 16, 17 • Type II compounds – ionic compounds made from transition metal and nonmetal; named by using stock system (using Roman Numerals) • Type III compounds – covalent compounds composed of 2 non-metals; named using prefixes

  12. LEQ: How do you name ionic compounds? • TYPE I COMPOUNDS • Write cation (metal) name first • Then, write the nonmetal name. Drop the ending and add –ideto the end • Ex. Nitride, sulfide, fluoride, oxide, bromide, iodide, chloride, telluride, phosphide

  13. LEQ: How do you name ionic compounds? If it is a ternary compound (with a polyatomic ion) First write name of cation Then write name of polyatomic ion

  14. LEQ: How do you name ionic compounds? • TYPE II COMPOUNDS (named using stock system) • If it is a transition metal, name the cation first, then put a Roman Numeral after its name to represent its oxidation number!!! • Look at the subscript of the nonmetal for this information!!! • Then name the anion. Remember to drop the ending and add –ide or if it is polyatomic name the polyatomic ion.

  15. LEQ: How do you name ionic compounds? • Practice Naming Ionic Compounds • MnO2 • Ca (NO3)2 • BaSO4 • Cu3P2 • AgCl • B2O3 • MgCl2 • Ba (OH)2

  16. LEQ: How do you name ionic compounds? • Practice Naming Ionic Compounds-Answers • MnO2 – Manganese (IV) oxide • Ca (NO3)2 – Calcium nitrate • BaSO4 – Barium sulfate • Cu3P2 – Copper (II) phosphide • AgCl – Silver (I) chloride • B2O3 – Boron oxide • MgCl2 – Magnesium chloride • Ba (OH)2 – Barium hydroxide

  17. LEQ: How do you name ionic compounds? • Bell Work 01/22/13 • Name the following ionic compounds • Be (OH)2 • Mn (NO3)3 • FePO4

  18. LEQ: How do you name ionic compounds? • Bell Work 01/22/13 • Name the following ionic compounds • Be (OH)2 – Beryllium hydroxide • Mn (NO3)3 – Manganese (III) nitrate • FePO4 – Iron (III) phosphate

  19. LEQ: How do you write the formula of an ionic compound? • Write the ions beside each other (first cation then anion) • Write the oxidation of each as superscripts w/ charge • Drop the +/- signs • Crisscross superscripts so they become subscripts • Reduce when possible

  20. LEQ: How do you write the formula of an ionic compound? Practice Write the formula for the following TYPE I compounds • Magnesium chloride • Potassium iodide

  21. LEQ: How do you write the formula of an ionic compound? Practice-Answers • Magnesium chloride- MgCl2 • Potassium iodide- KI

  22. LEQ: How do you write the formula of an ionic compound? Practice on your own Write the formula for the following Type I compounds • Boron oxide • Beryllium and Nitrogen

  23. LEQ: How do you write the formula of an ionic compound? Practice-Answers • Boron oxide- B2O3 • Beryllium and Nitrogen – Be3N2

  24. LEQ: How do you write the formula of an ionic compound? Write the formula unit for the following type I compounds: Lithium nitride Sodium fluoride

  25. LEQ: How do you write the formula of an ionic compound? Bell Work 1/15/13 Write the formula unit for the following: Lithium nitride – Li3N Sodium fluoride - NaF

  26. LEQ: How do you write the formula of an ionic compound? • How do you write the formula of an ionic compound with a transition metal? Written as Roman Numerals • Ti (4+, 3+) • Cr (2+, 3+, 6+) • Mn ( 3+, 4+, 6+) • Fe (2+, 3+) • Co (2+, 3+) • Ni (2+, 3+) • Cu (2+, 1+) • Ag (1+) • Zn (1+, 2+) • Pb (2+, 4+) • Sn (1+, 2+, 4+)

  27. LEQ: How do you write the formula of an ionic compound? • When it is a transition metal (type II compound). • First, write the symbol of the cation. Use the roman numeral for the oxidation number. • Then, write the symbol for the anion and use periodic table to determine its oxidation number. • Criss-cross oxidation numbers. • Reduce if necessary.

  28. LEQ: How do you write the formula of an ionic compound? Practice Write formula for the following • Iron (III) oxide • Zinc (II) chloride • Silver (I) chloride

  29. LEQ: How do you write the formula of an ionic compound? • Practice • Write formula for the following • Iron (III) oxide – Fe2 O3 • Zinc (II) chloride – Zn Cl2 • Silver (I) chloride – Ag Cl

  30. LEQ: How do you write the formula of an ionic compound? Practice Write formula for the following • Copper (II) phosphide • Manganese (IV) oxide • Lead (IV) sulfide

  31. LEQ: How do you write the formula of an ionic compound? • Practice • Write formula for the following • Copper (II) phosphide – Cu3 P2 • Manganese (IV) oxide – Mn O2 • Lead (IV) sulfide – Pb S2

  32. LEQ: How do you write the formula of an ionic compound? How do you write the formula of an ionic compound with a polyatomic ion? • Treat the polyatomic ion as one • Use parenthesis around polyatomic ion • Crisscross oxidation numbers to determine formula • Only reduce subscripts that are outside of the parenthesis

  33. Cation Anion LEQ: How do you write the formula of an ionic compound? • Ca 2+ • Mg 2+ • Ba2+ • Ba2+ NO 3– PO 43- OH – SO 4 2-

  34. LEQ: How do you write the formula of an ionic compound? Bell Work 1/23/13 Practice writing formulas with polyatomic ions Sodium carbonate Calcium carbonate Aluminum carbonate Sodium phosphate Calcium phosphate Aluminum phosphate

  35. LEQ: How do you write the formula of an ionic compound? Practice writing formulas with polyatomic ions Sodium carbonate – Na2CO3 Calcium carbonate – CaCO3 Aluminum carbonate – Al2(CO3)3 Sodium phosphate – Na3 PO4 Calcium phosphate – Ca3 (PO3)2 Aluminum phosphate – AlPO3

  36. LEQ: How do you write the formula for a covalent compound? • Between nonmetals and nonmetals • Type III Compounds that does not contain cations and anions • You do NOT crisscross to determine formula • Look at the name, it tells you the formula!!!! • You MUST KNOW AND USE prefixes (it tells the number of atoms of the element in the compound) • DO NOT REDUCE FORMULAS!!!

  37. LEQ: How do you write the formula for a covalent compound? • Prefixes • Mono- • Di- • Tri- • Tetra- • Penta- • Hexa- • Hepta- • Octa- • Nona- • Deca- RULE!!!! Do NOT use “mono” on the first element!

  38. LEQ: How do you write the formula for a covalent compound? • Practice writing covalent compound formulas • Dinitrogen trioxide • Carbon tetrahydride • Phosphorous pentoxide • Disulfurtrifluoride

  39. LEQ: How do you write the formula for a covalent compound? • Practice writing covalent compound formulas - Answers • Dinitrogen trioxide – N2O3 • Carbon tetrahydride – CH4 • Phosphorous pentoxide – PO5 • Disulfurtrifluoride – S2F3

  40. LEQ: How do you name covalent compounds? • First, use the nonmetal furthest to the left on the periodic table. If they are in the same group, write the element with the larger period number first. Write Prefix and name of element. DO NOT USE MONO!!! • Then, write the second nonmetal with prefix, root, ending in –ide. • Look at subscript to determine the prefix needed

  41. LEQ: How do you name covalent compounds? • Bell work 01/30/13 Name the following covalent compound! • PCl3 • NH3

  42. LEQ: How do you name covalent compounds? • Practice naming covalent compounds • PCl3 – Phosphorous trichloride • NH3 – nitrogen trihydride

  43. LEQ: How do you name covalent compounds? • Practice naming covalent compounds on worksheet

  44. Compounds with or without water • hydrates (compounds with water) • Name ionic compound as usual; but, water is covalent compound so must use prefixes • Ex. CaSO4· 2 H2O • Calcium sulfate dihydrate • Anhydrous (without water)

  45. LEQ: How do you name acids? • Binary Acid • H + element • Hydroic acid • H + F • Hydrofluoric acid

  46. LEQ: How do you name acids? • H + Polyatomic acid (“oxo” acids) • DO NOT START WITH HYDRO- • ate  ic • “I ate something ic-ky” • Nitrate  nitric acid • HNO3 • ite  ous • “I took a b-ite of something delicious” • Nitrite  nitrous acid • HNO2

  47. LEQ: How do you name bases? • Naming Bases • Name the metal CATION first; it keeps its name as listed in the Periodic Table. • The polyatomic ion "hydroxide" (-OH) also keeps its name. • Examples: • LiOH is "lithium hydroxide" • Ca(OH)2 is "calcium hydroxide" • NH4OH is "ammonium hydroxide"

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