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Chemical Nomenclature

Chemical Nomenclature. Learning Targets. Write name & write symbol of selected elements Write name & write formula of a variety of compounds. Naming Inquiry. Formula Name NaCl Sodium Chloride KI Potassium Iodide MgCl 2 Magnesium Chloride What is a binary compound?. Naming Inquiry.

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Chemical Nomenclature

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  1. Chemical Nomenclature

  2. Learning Targets • Write name & write symbol of selected elements • Write name & write formula of a variety of compounds.

  3. Naming Inquiry FormulaName NaCl Sodium Chloride KI Potassium Iodide MgCl2Magnesium Chloride What is a binary compound?

  4. Naming Inquiry FormulaName NaCl Sodium Chloride KI Potassium Iodide MgCl2Magnesium Chloride What does the chemical formula of each indicate?

  5. Naming Inquiry FormulaName NaCl Sodium Chloride KI Potassium Iodide MgCl2Magnesium chloride Why are there two chlorines for one magnesium?

  6. Naming Inquiry FormulaName NaCl Sodium Chloride KI Potassium Iodide MgCl2Magnesium Chloride What are some naming rules that can be discovered from these examples?

  7. Elements (periodic table) Symbols: come from the first letter, or first two letters of the element’s name. First letter is always UPPERCASE, second letter always lower case. Co, cobalt vs. CO, carbon monoxide No, nobelium vs. NO, nitrogen oxide Some use latin name for symbol, ex. Gold (latin name = aurum or Au)

  8. NOTES • Formula: Represents composition of a compound • Tells proportions of elements in a compound relative to each other. • Subscripts are used to indicate number of atoms of each element in a compound. (ALWAYS Whole numbers!!) • The subscript follows the atom or atoms it refers to. If subscript follows “( )” then everything inside the “( )” is multiplied by the subscript.

  9. Examples: CO2 One atom of C, 2 atoms of O H2O 2 atoms of H, one atom of O Fe3(PO4)2 3 atoms of Fe, 2 atoms of P & 8atoms of O

  10. Formulas, continued • All atoms have oxidation numbers (valence charge). This is the combining power of the atom. ex : Everything in Group 1 has a +1 charge. Group 17 has -1 charge Na +1 Cl -1 combined = 0 ** You want your valences to always = 0

  11. Examples continued • What happens when it doesn’t = 0? Mg+2 Cl-1 = 0 You add another Cl-1 -2 so… it now looks like this: MgCl2 Now the “combined power” is 0

  12. You Try Ca+2 N-3 K+ P-3 Al+3 O-2

  13. Polyatomic ions or “radicals” are groups of atoms that behave as if they are single atoms. They also have oxidation numbers. Examples: SO4-2 (sulfate ion), NO3-1 (nitrate ion)

  14. We will use the concept of valence to write formulas • Valence is either “+” or “-” • In ALL compounds, the sum of the valences adds up to zero. • Metals are always “+” • Non-metals can be “+” or “-” • Most radicals are “-”, only common “+” radical is NH4+1 (ammonium)

  15. Application Example 1: Lithium Chloride …Li 1+ and Cl 1-, so the formula must be LiCl. Example 2: Calcium Oxide …Ca 2+ and O 2-, so the formula must be CaO Example 3: What about Lithium Oxide? Answer: you need two lithium atoms for every one oxygen to balance…Li2O

  16. Atoms that have a constant valence: (+1) = first column and Ag, (+2) = 2nd column plus Zn and Cd (+3) Al. (See columns already marked on your periodic table.) (H can be -1 in some special cases)

  17. Naming Binary Salts & Writing their Formulas Metal plus a non-metal (two elements). Named by adding the name of the first element (metal) to the second element (non-metal) whose name is modified to end in “ide.” Examples: oxygen becomes “oxide” chlorine becomes “chloride” sulfur becomes “sulfide” etc…

  18. Now… The Rules • Rule #1: ends in “ide” = Binary salt NaCl Sodium chloride Al2O3 Aluminum oxide KI Potassium iodide • Rule #2: valences must = 0

  19. Most metals have a variable valence and this must be indicated in the name of the compound. • The Stock System: The valence (+) of the metal is given as a Roman numeral. • Iron (Fe) can either be Fe+2 or Fe+3 therefore both forms exist in compounds. • Iron (II) chloride = FeCl2 • Iron (III) chloride = FeCl3 • The Latin names ferrous (for Fe +2) and ferric (for Fe+3) may also be used.

  20. How does the Stock System Work? • For metals in Groups 3-15 • Iron (II) chloride = FeCl2 • The (II) tells me the valence of Fe. • I know that each Cl has a -1 charge. I have 2 Cl’s for a total charge of -2, so the Fe has to be +2 to make the valences add up to zero • FeCl3 what is the oxidation of Fe? • Iron (III) chloride, Fe+3

  21. You Try - • Write the name or the formula using the Stock System • CuCl • Copper (I) chloride • CrO3 • Chromium (VI) oxide • Tin (IV) oxide • SnO2 • Nickel (II) oxide • NiO

  22. End notes 10/5 & 10/6

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