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Chemical Nomenclature

Chemical Nomenclature. Nomenclature. A System of Naming Compounds Compounds are two or more atoms of different elements bonded together. “Perhaps one of you gentlemen would mind telling me just what is outside the window that you find so attractive..?”. Image courtesy NearingZero.net.

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Chemical Nomenclature

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  1. Chemical Nomenclature

  2. Nomenclature • A System of Naming Compounds • Compounds are two or more atoms of different elements bonded together.

  3. “Perhaps one of you gentlemen would mind telling me just what is outside the window that you find so attractive..?” Image courtesy NearingZero.net

  4. Binary compounds • Binary Compounds • Compounds composed of two elements • Two types • Ionic • Covalent

  5. -- 1+ 2+ 3+ -- 3- 2- 1- Generally metals form cations and non-metals form anions.

  6. Ions… • Electrons are arranged on levels or “shells”. Atoms are most stable with 8 electrons on their outermost shell. This is often referred to as the octet rule. • Number of electrons on the outer shell = Group number for elements in “TALL” Groups I-8

  7. Step 4: AlCl 3 Example: Aluminum Chloride Criss-Cross Rule Step 1: Aluminum Chloride write out name with space Al Cl 3+ 1- Step 2: write symbols & charge of elements Al Cl Step 3: 1 3 criss-cross charges as subsrcipts combine as formula unit (“1” is never shown)

  8. Example: Aluminum Sulfide Criss-Cross Rule Step 1: Aluminum Chloride Step 2: Al3+ S2- Step 3: Al S 2 3 Step 4: AlS 3 2

  9. Example: Aluminum Oxide Criss-Cross Rule Step 1: Aluminum Oxide Step 2: Al3+ O2- Step 3: Al O 2 3 Step 4: Al2O3

  10. Example: Magnesium Oxide Criss-Cross Rule Step 1: Magnesium Oxide Step 2: Mg2+ O2- Step 3: Mg O 2 2 Step 4: Mg2O2 If you end up with a common denominator then you must reduce! Step 5: MgO

  11. + Ions…explained.. • Na Group 1 1 electron on outer shell O will lose 1 e- to expose the complete inside shell. • Now #e- = 10 but #p+ = 11 so the sodium is an ion with the formula Na1+. • Mg Group 2 2 electrons on outer shell Mg will lose 2 e- • Now #e- = 10 but #p+ = 12 so the magnesium is an ion with the formula Mg2+

  12. - Ions… explained… • To achieve the octet, atoms with more than 4 electrons on the outer shell will gain enough electrons to reach 8. • Cl Group 7 7 electrons on outer shell Cl will gain 1 e- . • Now #e- = 18 but #p+ = 17 so the chlorine is an ion with the formula Cl1-.

  13. 10/31 Ions…let’s figure some out...Complete the following table using the periodic table:

  14. Naming binary ionic compounds The name of the cation (+ charged ion) & write it first, followed by the anion (- charged ion). The name of the cation is the same as the name of the metal. The name of the anion (- charged ion) takes the root of the nonmetal name and adds the suffix -ide. Calcium and oxygen  calcium oxide. Aluminum and sulfur  aluminum sulfide.

  15. Ionic Compounds • Ionic Compounds • often a metal + nonmetal • anion (nonmetal), change endging to “-ide” • Rules for naming Ionic Compounds • All compound must be neutral UNLESS indicated otherwise. • The cation is always named first and the anion second • The cation takes the name of the element • The anion is named by the root of the element name and changing the ending to “-ide”. • Ex. Chlorine becomes Chloride

  16. Naming Ionic Binary Compounds

  17. "GREEDY" with their electrons "GENEROUS" NON-METALS METALS

  18. Naming Binary Compounds:Complete the following: Formula Name barium oxide • BaO ____________________ • ________________ sodium bromide • MgI2 ____________________ • KCl ____________________ • ________________ strontium fluoride • ________________ cesium fluoride NaBr magnesium iodide potassium chloride SrF2 CsF

  19. Binary Ionic Compounds • Cations (positively charged ions) and anions (negatively charged ions) will associate with each other and form a neutral binary compound to reduce energy . • 1 Na+ 1 Cl- NaCl • 1 Ca2+ 1 O2- CaO • 3 K+ 1 N3- K3N • 2 Al3+ 3 S2- Al2S3

  20. Examples barium chloride BaCl2 potassium oxide K2O magnesium hydroxide * Mg(OH)2 potassium nitrate KNO3 * Has more than 2 elements in it, so it has a polyatomic ion present

  21. Common Monatomic Cations and Anions

  22. "GREEDY" with their electrons "GENEROUS" NON-METALS METALS

  23. Keeping Track of Electrons • The electrons responsible for the chemical properties of atoms are those in the outer energy level. • Valence electrons - electrons in the outer energy level. • Core electrons -those in the energy levels below.

  24. Keeping Track of Electrons • Atoms in the same column • Have the same outer electron configuration. • Have the same valence electrons. • Easily found by looking up the group number on the periodic table. • Group 2A - Be, Mg, Ca, etc.- • 2 valence electrons

  25. Lewis or Electron Dot Diagram: 1) Count up total number of valence electrons 2) Connect all atoms with single bonds - “multiple” atoms usually on outside - “single” atoms usually in center; C always in center, H always on outside. (not H, though) 3) Complete octets on exterior atoms 4) Check - all atoms (except H) have an octet; if not, try multiple bonds - any extra electrons? Put on central atom

  26. Lewis Dot Diagram • Write the element symbol. • Carbon is in the 4th group, so it has 4 valence electrons. • Starting at the top or the right, draw 4 electrons, or dots, counter-clockwise around the element symbol. C

  27. Lewis Dot Diagram • Check your work. • Using your periodic table, check that Carbon is in the 4th group. • You should have 4 total electrons, or dots, drawn in for Carbon. C

  28. 11/1SOME Transition metal & metalloids may have different oxidation charge than just a +2 & require the use a Roman Numeral: • Reverse the subscripts to find the oxidation charge for a metal & write with Roman numerals in ( ) after the metal in the compound name. You can put the (II) even for the +2 ones but not really required to do so. Iron(II) chloride FeCl2 2 Cl so Fe is +2 FeCl3 3 Cl so Fe is +3 Iron(III) chloride Cr2S3 3 S-2 -6 so Cr is +3 (6/2) chromium(III) sulfide

  29. Common Type II Cations

  30. Name the following & check to see if they need a Roman numeral in the name:

  31. Write the following compounds from the names:

  32. 11/1Polyatomic Ion Compounds – means 3 or more elements present Ternary compounds are those containing three different elements. (NaNO3, NH4Cl, etc.). The naming of ternary compounds involves the memorization of several positive and negative polyatomic ions, (two or more atoms per ion), and adding these names to the element with which they combine. i.e., Sodium ion, Na1+ added to the nitrate ion, NO31-, to give the compound, NaNO3, sodium nitrate. Binary rules for indicating the oxidation number of metals and for indicating the numbers of atoms present are followed. The polyatomic ions are listed in a separate handout.

  33. NH41+ …………… OH1- …………… CN1- ………….. ammonium hydroxide cyanide Polyatomic Ions - Memorize Eight “-ATE’s” PO43- …………… SO42- …………… CO32- ………….. ClO31- ………….. NO31- ………..…. phosphate sulfate carbonate chlorate nitrate phosphATE sulfATE carbonATE chlorATE nitrATE Exceptions:

  34. Common Polyatomic Ions Names of Common Polyatomic Ions Ion Name Ion Name NH41+ ammonium CO3 2- carbonate NO21- nitrite HCO31- hydrogen carbonate NO31- nitrate (“bicarbonate” is a widely SO32- sulfite used common name) SO42- sulfate ClO 1- hypochlorite HSO41- hydrogen sulfate ClO21- chlorite (“bisulfate” is a widely ClO31- chlorate used common name) ClO41- perchlorate OH 1- hydroxide C2H3O22- acetate CN 1- cyanide MnO41- permanganate PO43- phosphate Cr2O72- dichromate HPO42- hydrogen phosphate CrO42- chromate H2PO41- dihydrogen phosphate O22- peroxide Print Version Zumdahl, Zumdahl, DeCoste, World of Chemistry2002, page 100

  35. Ternary Compounds NaNO2 KClO3 Ca3(PO4)2 Fe(OH)3 NaHCO3 sodium nitrite potassium chlorate calcium phosphate iron (III) hydroxide sodium bicarbonate Or sodium hydrogen carbonate

  36. Rules for Parentheses Parentheses are used only when the following two condition are met: • There is a radical (polyatomic ion) present and… • There are two or more of that radical in the formula. Examples: NaNO3 NO31- is a radical, but there is only one of it. Co(NO3)2 NO31- is a radical and there are two of them (NH4)2SO4 NH41+ is a radical and there are two of them; SO42- is a radical but there is only one of it. Co(OH)2 OH1- is a radical and there are two of it. Al2(CO3)3 CO32- is a radical and there are three of them. NaOH OH1- is a radical but there is only one of it.

  37. 11/2 Check for understanding… Check all compounds starting with a transition metal or metalloid for the charge that it has & if the charge used in the compound is different than the PT then must add a Roman numeral in the name to clarify the charge used. • Write the correct name for each of these compounds: • Fe(OH)2 • (NH4)3PO4 • AlPO4 • Cu(C2H3O2)2 • CaCO3 • NH4OH • Cr2(SO4)3 • Mg(NO3)2

  38. Lewis or Electron Dot Diagrams 1. Draw the Lewis dot diagrams for the following: • H • P • Ca • Ar • Cl • Al C

  39. 11/4 Ionic or covalent? IONIC compound:is the transfer of e- that contains a metal and a nonmetal in its formula • The metal will give up e- causing a + charge item to the nonmetal resulting in a – charge part of the compound • Na+1 Cl-1 NaCl Covalent compound: is the sharing of valence e- that is made up of 2 nonmetal Uses a different set up rules for naming than ionic compounds Ex. CO carbon monoxide

  40. 11/7Identify if the following as ionic or a covalent compound: 11. Explain how you know if these are ionic or covalent compounds? 1. Fe(OH)4 2. CO2 3. (NH4)3PO4 4. AlPO4 5. Cu(C2H3O2)3 6. I2P5 7. CO3 8. CaCO3 9. NH4OH 10. H20

  41. Covalent Bonding • Bonds between atoms are formed through the sharing of electrons • Covalent bonds form between two non-metal atoms through sharing of pairs of electrons • Atoms have a “desire” to have their outer energy levels filled (Octet Rule) • Covalent bonding can be represented with Lewis Dot Diagrams

  42. 11/7 Covalent Naming • Nonmetals hold onto their valence electrons. • They can’t give away electrons to bond. • Get it by sharing valence electrons with each other. • Different from an ionic bond because they actually form molecules. • Called a binary molecular compound • The first vowel is often dropped to avoid the combination of “ao” or “oo”. CO = carbon monoxide (monooxide

  43. YOU must know these: Greek Prefixes for Two Nonmetals Number Indicated Prefixes 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-

  44. Binary Molecular Compounds N2O dinitrogen monoxide N2O3dinitrogen trioxide N2O5dinitrogen pentoxide ICl iodine monochloride ICl3 iodine trichloride SO2 sulfur dioxide SO3 sulfur trioxide

  45. 11/7 Name the following covalent compounds: 1) NO _________________ 2) N3O7_________________ 3) N2O3__nitrogen _____oxide 4) I P _________________ 5) ICl4_________________ 6) SO3_________________ 7) SO2_________________ 2 5

  46. Write the covalent formulas for the following: • 1. diphosphorous pentoxide • 2. Nitrogen trifluoride • 3. Dinitrogen pentoxide • 4. sulfur dioxide • 5. carbon tetrachloride • 6. carbon monoxide • 7. phosphorous pentabromide

  47. 11/9Draw the Lewis electron dot diagram for the following, include the oxidation charge on each & name them: • 1. MgI2 • 2. CaO • 3. NaCl • 4. AlF3

  48. Vocabulary CHEMICAL FORMULA IONIC COVALENT formula unit molecular formula NaCl CO2

  49. Vocabulary COMPOUND more than 2 elements 2 elements binary compound ternary compound NaCl NaNO3

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