1 / 59

Classifying Materials

Learn about the classification of materials into atomic elements, molecular elements, molecular compounds, and ionic compounds. Understand the molecular view of elements and compounds, as well as how to classify different substances.

sloana
Télécharger la présentation

Classifying Materials

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Classifying Materials • Atomic elements = elements whose particles are single atoms. • Molecular elements = elements whose particles are multi-atom molecules. • Molecular compounds = compounds whose particles are molecules made of only nonmetals. • Ionic compounds = compounds whose particles are cations and anions.

  2. Molecular View of Elements and Compounds

  3. Molecular Elements • Certain elements occur as 2 atom molecules • Rule of 7’s • there are 7 common diatomic elements • find the element with atomic number 7, N • make a figure 7 by going over to Group 7A, then down • don’t forget to include H2 VIIA 7 H2 N2 O2 F2 Cl2 Br2 I2

  4. Ionic Compounds • Ionic compounds form when metals combine with nonmetals. • There are no individual molecules, instead there is a 3-dimensional array made up of formula units of cations and anions. • metal atoms form cations, nonmetal atoms for anions • Compounds must have no total charge, therefore we must balance the numbers of cations and anions in a compound to get 0 charge • If Na+ is combined with S2-, you will need 2 Na+ ions for every S2- ion to balance the charges, therefore the formula must be Na2S

  5. Molecular Compounds • two or more nonmetals • smallest unit is a molecule

  6. Classify each of the following as either an atomic element, molecular element, molecular compound or ionic compound • aluminum, Al • aluminum chloride, AlCl3 • chlorine, Cl2 • acetone, C3H6O • carbon monoxide, CO • cobalt, Co

  7. Classify each of the following as either an atomic element, molecular element, molecular compound or ionic compound • aluminum, Al = atomic element • aluminum chloride, AlCl3= ionic compound • chlorine, Cl2= molecular element • acetone, C3H6O = molecular compound • carbon monoxide, CO = molecular compound • cobalt, Co = atomic element

  8. Metal Cations • Type I • metals whose ions can only have one possible charge • IA, IIA, (Al, Ga, In) • determine charge by position on the Periodic Table • IA = +1, IIA = +2, (Al, Ga, In = +3) • Type II • metals whose ions can have more than one possible charge • determine charge by charge on anion How do you know a metal cation is Type II? It’s not Type I !!!

  9. Determine if the following metals are Type I or Type II. If Type I, determine the charge on the cation it forms. • lithium, Li • copper, Cu • gallium, Ga • tin, Sn • strontium, Sr

  10. Determine if the following metals are Type I or Type II. If Type I, determine the charge on the cation it forms. • lithium, Li Type I +1 • copper, Cu Type II • gallium, Ga Type I +3 • tin, Sn Type II • strontium, Sr Type I +2

  11. Type I Binary Ionic Compounds • Contain a Metal Cation + a Nonmetal Anion • Common simple cations and anions are listed in Table 5.1 • The Metal is listed first in the formula & name • Name the metal cation first, name the nonmetal anion second. • The cation name is the same as the metal name. • The nonmetal anion is named by changing the ending on the nonmetal name to –ide

  12. Example – Naming Binary Ionic, Type I Metal CsF 1. Identify Major ClassCs = is a metal because it is on the left side of the Periodic Table F = is a nonmetal because it is on the right side of the Periodic Table: Ionic • Identify the Subclass 2 elements: Binary Ionic 3. Is the metal Type I or Type II? Cs is in Group IA: Type I 4. Identify the cation and anion Cs = Cs+ because it is in Group 1 F = F- because it is in Group 7 • Name the cation Cs+ = cesium 6. Name the anion F- = fluoride 7. Write the cation name first, then the anion name cesium fluoride

  13. Type II Binary Ionic Compounds • Contain a Metal Cation + a Nonmetal Anion • Metal ions are listed first in the formula & name • Name the metal cation first, name the nonmetal anion second. • Metal cation names are the metal name followed by a Roman Numeral in parentheses to indicate the charge on the cation. • determine charge from the anion charge • Common Type II cations (elements that have more than one possible charge) are listed in Table 5.2 • Nonmetal anions are named by changing the ending on the nonmetal name to -ide

  14. Example – Naming Binary Ionic, Type II MetalCuCl 1. Identify Major Class Cu = is a metal because it is on the left side of the PT Cl = is a nonmetal because it is on the right side of the PT  Ionic • Identify the Subclass 2 elements,  Binary Ionic 3. Is the metal Type I or Type II Cu is not in Group IA, IIA, or (Al, Ga, In)  Type II 4. Identify cation and anion Cl = Cl- because it is Group 7 Cu = Cu+ to balance the charge • Name the cation Cu+ = copper(I) 6. Name the anion Cl- = chloride 7. Write the cation name first, then the anion name copper(I)chloride

  15. Determining the Charge on a Multivalent Cation – Au2S3 • determine the charge on the anion Au2S3 - the anion is S, since it is in Group 6A, its charge is -2 • determine the total negative charge since there are 3 S in the formula, the total negative charge is -6 • determine the total positive charge since the total negative charge is -6, the total positive charge is +6 • divide by the number of cations since there are 2 Au in the formula & the total positive charge is +6, each Au has a +3 charge

  16. Examples: Name the following • LiCl • AlCl3 • PbO • PbO2 • Mn2O3 • ZnCl2 • AgCl

  17. Examples • LiCl = lithium chloride • AlCl3 = aluminum chloride • PbO = lead(II) oxide • PbO2 = lead(IV) oxide • Mn2O3 = manganese(III) oxide • ZnCl2 = zinc(II) chloride or zinc chloride • AgCl = silver(I) chloride or silver chloride

  18. Naming Type III Binary Molecular Compounds of 2 Nonmetals • Name the first element in the formula first • use the full name of the element • Name the second element in the formula with an -ide • as if it were an anion, however, remember these compounds do not contain ions! • Use a prefix in front of each name to indicate the number of atoms Never use the prefix mono- on the first element

  19. Subscript - Prefixes • 1 = mono- • not used on first nonmetal • 2 = di- • 3 = tri- • 4 = tetra- • 5 = penta- • 6 = hexa- • 7 = hepta- • 8 = octa- • drop the last “a” if the name begins with a vowel Remember these prefixes listed in Table 5.3

  20. Example – Naming Binary MolecularBF3 1. Identify Major Class B = is a nonmetal because it is on the right side of the PT F = is a nonmetal because it is on the right side of the PT  Molecular • Identify the Subclass 2 elements:  Binary Molecular • Name the first element boron • Name the second element with an –ide fluorine fluoride • Add a prefix to each name to indicate the subscript monoboron, trifluoride • Write the first element with prefix, then the second element with prefix • Drop prefix mono from first element borontrifluoride

  21. Compounds Containing Polyatomic Ions • Polyatomic ions are single ions that contain more than one atom. • Name these compounds using procedures similar to those for naming binary ionic compounds. • Use Table 5.4 to help you recognize these ions until you have memorized them. • Note that several polyatomic anions exist that contain an atom of a given element and different numbers of oxygen atoms. These anions are called oxyanions. E.g. oxyanions containing chlorine are: • ClO-hypochlorite • ClO2- chlorite • ClO3- chlorate • ClO4-perchlorate

  22. Some Common Polyatomic Ions

  23. symbol of the polyatomic ion called nitrate symbol of the polyatomic ion called sulfate implied “1” subscript on magnesium implied “1” subscript on calcium parentheses to group two NO3’s no parentheses for one SO4 Molecules with Polyatomic Ions Mg(NO3)2 compound called magnesium nitrate CaSO4 compound called calcium sulfate

  24. subscript indicating two NO3 groups no subscript indicating one SO4 group implied “1” subscript on nitrogen, total 2 N implied “1” subscript on sulfur, total 1 S stated “4” subscript on oxygen, total 4 O stated “3” subscript on oxygen, total 6 O Molecules with Polyatomic Ions Mg(NO3)2 compound called magnesium nitrate CaSO4 compound called calcium sulfate

  25. Example – Naming Ionic Substances when there is a Polyatomic Ion: Na2SO4 • Identify Major Class: Na is a metal because it is on the left side of the PT SO42- is a polyatomic ion:  Ionic • Identify the Subclass: compound has 3 elements:  Ionic with a Polyatomic Ion 3. Is the metal Type I or Type II? Na is in Group IA: Type I • Identify the ions: Na = Na+ because it is in Group 1 SO42- = SO42- is a polyatomic ion • Name the cation: Na+ = sodiumion (Type I) 6. Name the anion: SO42- = sulfate ion 7. Write the name of the cation followed by the name of the anion sodiumsulfate

  26. Example – Naming Ionic substances with Polyatomic Ion: Fe(NO3)3 1. Identify Major Class: Fe = is a metal because it is on the left side of the Periodic Table NO31- = is a polyatomic ion: Ionic • Identify the Subclass: there are 3 elements:  Ionic with a Polyatomic Ion • Is the metal Type I or Type II? Fe is not in Group IA, IIA, or (Al, Ga, In):  Type II 4. Identify the ions: NO3 = NO3- is a polyatomic ion Fe = Fe+3 to balance the charge of the 3 NO3-1 • Name the cation: Fe+3 = iron(III) ion (Type II) 6. Name the anion: NO3- = nitrate ion 7. Write the name of the cation followed by the name of the anion iron(III)nitrate

  27. Additional Examples Name the following compounds: PbCO3 Ca(HCO3)2 Fe(OH)2 Cu(NO3)2 NH4I KHSO4

  28. Additional Examples Name the following compounds: PbCO3 lead(II) carbonate Ca(HCO3)2 calcium hydrogen carbonate Fe(OH)2 iron(II) hydroxide Cu(NO3)2 copper(II) nitrate NH4I ammonium iodide KHSO4 potassium hydrogen sulfate

  29. Naming Acids • Contain H3O+1 cation and an anion in an aqueous solution • Binary acids have H3O+1 cation and a nonmetal anion • Oxyacids have H3O+1 cation and a polyatomic anion • Acids are molecular compounds that often behave like they are made of ions • All names have acid at the end • Binary Acids = hydro prefix + stem of the name of the nonmetal + ic suffix See Table 5.5 • Oxyacids See Table 5.6 • if the polyatomic ion ends in –ate = name the polyatomic ion with an –ic suffix • if the polyatomic ion ends in –ite = name the polyatomic ion with an –ous suffix

  30. Example – Naming Binary AcidsHCl • Identify Major Class: first element listed is H,  Acid • Identify the Subclass: 2 elements,  Binary Acid • Identify the anion: Cl = Cl-, chloride because it is in Group 7A • Name the anion with an –ic suffix: Cl- = chloride  chloric • Add a hydro- prefix to the anion name: hydrochloric • Add the word acid to the end: hydrochloricacid

  31. Example – Naming OxyacidsH2SO4 • Identify Major Class: first element listed is H,  Acid • Identify the Subclass: 3 elements in the formula,  Oxyacid 3. Identify the anion: SO4 = SO42- = sulfate • If the anion has –ate suffix, change it to –ic. If the anion has –ite suffix, change it to –ous:SO42- = sulfatesulfuric • Write the name of the anion followed by the word acid sulfuric acid

  32. Example – Naming Oxyacids H2SO3 • Identify Major Class: first element listed is H,  Acid • Identify the Subclass: 3 elements in the formula,  Oxyacid • Identify the anion: SO3 = SO32- = sulfite • If the anion has –atesuffix, change it to –ic. If the anion has –ite suffix, change it to –ous: SO32- = sulfite  sulfurous • Write the name of the anion followed by the word acid sulfurous acid

  33. Additional Examples Name the following acids: • HF • H3PO3 • HNO3 • HBrO4 • H2S

  34. Additional Examples Name the following acids: • HF hydrofluoric acid • H3PO3 phosphorous acid • HNO3 nitric acid • HBrO4 perbromic acid • H2S hydrosulfuric acid

  35. Formula-to-Name Flow Chart

  36. Formula-to-NameStep 1 Is the compound one of the exceptions to the rules?

  37. Common Names - Exceptions • H2O = water, steam, ice • NH3 = ammonia • CH4 = methane • NaCl = table salt • C12H22O11 = table sugar

  38. Formula-to-NameStep 2 What major class of compound is it? Ionic or Molecular

  39. Major Classes • Ionic • metal + nonmetal • The metal is written first in the formula • Binary Ionic • compounds with polyatomic ions • Molecular • 2 nonmetals • Binary Molecular (or Binary Covalent) • Acids – formula starts with H • although acids are molecular, they behave as ionic substances when dissolved in water • They may be binary or an oxyacid

  40. Formula-to-NameStep 3 What major subclass of compound is it? Binary Ionic, Ionic with Polyatomic Ions, Binary Molecular, Binary Acid, Oxyacid

  41. Classifying Compounds into major subclasses • Compounds containing a metal and a nonmetal = binary ionic • Type I and II • Compounds containing two nonmetals = binarymolecular compounds –Type III • Compounds containing a polyatomic ion = ionic with polyatomic ion • Compounds containing H and a nonmetal = binary acids • Compounds containing H and a polyatomic ion = oxyacids

  42. Formula-to-NameStep 4 Apply Rules for the Class and Subclass

  43. Formula-to-NameRules for Ionic • Made of cations and anions • Name by simply naming the ions • If the cation is: • Type I metal = metal name • Type II metal = metal name with the charge written in parentheses as a Roman Numeral • Polyatomic ion = name of polyatomic ion • If the anion is: • Nonmetal = stem of nonmetal name + ide • Polyatomic ion = name of polyatomic ion

  44. Monatomic Nonmetal Anion • determine the charge from the position on the Periodic Table • to name the anion, change the ending on the element name to –ide

  45. BO3-3 CO3-2 NO3-1 SiO3-2 PO4-3 SO4-2 ClO3-1 AsO4-3 SeO4-2 BrO3-1 TeO4-2 IO3-1 Periodic Pattern of Polyatomic Ions-ate groups IIIA IVA VA VIA VIIA

  46. Patterns for Polyatomic Ions • -ate ion • chlorate = ClO3-1 • -ate ion + 1 O  same charge, per- prefix • perchlorate = ClO4-1 • \ • -ate ion – 1 O  same charge, -ite suffix • chlorite = ClO2-1 • -ate ion – 2 O  same charge, hypo- prefix, -ite suffix • hypochlorite = ClO-1

  47. Practice - What are the formulas for compounds made from the following ions? • copper(II) ion with a nitride ion • iron(III) ion with a bromide ion • aluminum ion with a sulfate ion

  48. Cu2+ with N3- Cu3N2 • Fe+3 with Br- FeBr3 • Al+3 with SO42-Al2(SO4)3

  49. Formulas Describe Compounds • A compound is a distinct substance that is composed of atoms of two or more elements. • Formulas describe a compound by showing the number and type of each atom in the simplest unit of the compound: • molecules or ions: H2O, NaCl • Each element in a compound formula is represented by the chemical symbol that identifies the element: NaCl, sodium chloride • The number of atoms of each element is written to the right of the element as a subscript: • if there is only one atom, the 1 subscript is not written and is understood: CO, carbon monoxide; CO2, carbon dioxide • polyatomic groups are placed in parentheses: • if more than one group is part of the formula the number of groups is written as a subscript:

  50. Formulas Describe Compounds Water = H2O – two atoms of hydrogen and 1 atom of oxygen Table sugar = C12H22O11 – 12 atoms of C, 22 atoms of H and 11 atoms of O

More Related