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Chemical Names and Formulas

Chemical Names and Formulas. Molecules. A molecule is the smallest electrically neutral unit of a substance that still has the properties of the substance. 1. Monatomic - consist as a single atom (Ex: Noble gases) 2. Diatomic molecule - 7 exist in nature “BrINCl HOF”

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Chemical Names and Formulas

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  1. Chemical Names and Formulas

  2. Molecules A molecule is the smallest electrically neutral unit of a substance that still has the properties of the substance. 1. Monatomic - consist as a single atom (Ex: Noble gases) 2. Diatomic molecule -7 exist in nature “BrINCl HOF” 3. Triatomic molecule ( Ex: O3 -ozone) He Br2 I2 N2 Cl2 H2 O2 F2 (means 2) atoms

  3. Chemical Formula: shows the kinds and numbers of atoms in the smallest representative unit of the substance (formula unit) H2O H2O2 What’s the difference between these two formulas? When you change the subscripts the formula no longer represents that compound. • REMEMBER!!!! • H – Element symbol always begins with • a capital letter • Na – If symbol has two letters, the second • letter is always lowercase

  4. Chemical Formulas How to read formulas: H2O = 2 hydrogen atoms 1 oxygen atom Ca(OH)2 – Number outside the parenthesis distributes to inside the parenthesis 1 calcium atom 2 oxygen atoms 2 hydrogen atoms

  5. Explain the following: MgCl2 – What elements are present? How many? Mg - Cl - Pb(NO3)2 – What elements are present? How many? Pb - N - O - 1 2 1 2 6

  6. Ionic Charges of Representative Elements

  7. Oxidation Numbers – how many electrons an atom would gain or lose to follow the octet rule (also called its charges) +1 +2 -3 -2 -1 +3

  8. Charges of Transition Metals These transition metals have more than one charge: Cr2+ or 3+ Cu+ or 2+ Mn2+ or 3+ Sn2+ or 4+ Fe2+ or 3+ Pb2+ or 4+ Co2+ or 3+ Ni2+ or 3 + Hg1+ or 2+ Au1+ or 3 + Sc2+ or 3+ Hg1+ or 2 +

  9. I. Writing Formulas for Binary Ionic Compounds The cation is always written first! Rules: • Write symbol and charge for both cation and anion. • Crisscross charges, drop the charge and write as subscripts. • CHECK!! The formula must be in the lowest possible ratio.

  10. Example Problems +2 - I Ca 1 2 CaI2 Write formulas for these compounds: calcium iodide

  11. Tin (IV) oxide +4 -2 Sn O 2 4 Sn2O4 SnO2

  12. White Board Practice Aluminum sulfide -2 +3 Al S 2 3 Al2S3

  13. Beryllium Oxide -2 +2 Be O 2 2 BeO Be2O2

  14. II. Naming Binary Ionic Compounds 1.) Use the name of the cation. ****Use Roman Numerals if Transition Metal. 2.) Name the anion and change ending to -ide.

  15. Naming Binary Ionic Compounds +2 -1 -2 +4 Find Sn Where is it located? Use Roman Numerals Tin (IV) Sulfide SnS2

  16. WHITE BOARD practice problems A.) KCl B.) CuBr2 C.) AlF3 D.) MgO E.) MnI2

  17. Al+3 P-3

  18. White Board Practice 1.) K+ S-2

  19. 2.) Al+3 I-

  20. 3.) Ag+ O-2

  21. 4.) Ni+2 O-2

  22. 5.) Pb+4 O-2

  23. Polyatomic Ions Tightly bound groups of atoms that behave as a unit and carry a charge. Examples: Ammonium NH4+ Cyanide CN- Sulfite SO32-

  24. III. Writing Formulas for Ternary Ionic Compounds A. Contain a polyatomic ion Same rules as for binary ionic compounds. Name the cation ***Use a Roman numeral if necessary Name the anion (change ending to –ide) Polyatomic ions will stay the same!! Use parenthesis if there is more than one polyatomic ion

  25. Boron acetate B3+ C2H3O2-1 Magnesium Dichromate Mg+2 Cr2O7-2

  26. White Board Practice Problems Write formulas for the following ternary ionic compounds: Calcium Carbonate Barium Nitrite Potassium Sulfate Magnesium Phosphate

  27. White Board Practice Problems: Name the following ternary ionic compounds: NaCN NH4ClO Li2SO3 CaC2O4 Al(OH)3 Sn3(PO4)2

  28. V. Rules for Naming Covalent Molecules 1. Prefixes are used to show how many atoms of each element are present in the molecules Prefixes used for Naming Binary Covalent Compounds

  29. 2. Second element is written with an –ide ending. ***All binary compounds, both ionic and covalent end in –ide. 3. The vowel at the end of the prefix is dropped when the name of the element begins with the same vowel. Ex: monoxide, not monooxide Rules for Naming Covalent Molecules

  30. 4. Mono is omitted if there is just a single atom on the first element in the name. Ex: CO2 carbon dioxide not monocarbon dioxide Rules for Naming Covalent Molecules

  31. Naming Binary Covalent Molecules 1.) CO 2.) SO2 3.) N2O 4.) CCl4 5.) N2O5 6.) NO4 7.) OF2

  32. Writing Formulas for Binary Covalent Molecules Write the formulas for the following compounds. 1. carbon monochloride 2. nonacarbon tetrachloride 3. heptabromine dioxide 4. phosphorus trichloride 5. octanitrogen pentafluoride

  33. Ionic vs. Covalent Are the following compounds ionic or covalent? a. H2O f. dinitrogen tetraoxide g. FeS b. Sodium chloride c. CuSO4 h. Cobalt (III) chloride d. CO i. H2S e. Lithium hydroxide j. PF3

  34. Naming Acids • 1. All acids begin with H • 2. If it is just H and another element, the name begins with “Hydro” the other element with its suffix changed to “ic” • HCl- Hydrochloric Acid • HI- Hydroiodic Acid • H2S- Hydrosulfuric Acid

  35. Naming Acids (Cont.) • 3. If the acid contains a polyatomic ion, you only change the name of the polyatomic ion • ate goes to ic • ite goes to ous • H2SO4- Sulfuric Acid • H2SO3- Sulfurous Acid

  36. Naming Acids • HCl • H2SO4 • HNO2 • HC2H3O2 • H3PO3 • H2CO3

  37. Relay Challenge 1.) How many atoms of fluorine are present in CF4? 2.) How many atoms of carbon are present in CF4? 3.) What is the formula for carbon monoxide? 4.)What is the formula for lithium chloride? 5.) What is the formula for the compound formed by iron (II) and carbonate ions? 6.) What is the formula for aluminum hydroxide? 7.) What is the formula for lead (IV) oxide? 8.) What is the formula for magnesium nitrate? 9.) What is the name of the compound: NH3? CCl4? 10.) What is the cation in iron (II) oxide? 11.) What is the name of the compound N2O2? H2O2? 12.) What is the formula for sulfur trioxide? 13.) What is the formula for dinitrogen tetrafluroide? 14. )What prefix is used to represent ten? 15.) How do you know a compound is covalent when looking at the chemical formula? 16.) Using the ion pairs listed, write the correct chemical formula that the ions would form: a. Cr+3 I- = b. Cu+2 O-2 = c. Li+ S-2 = 17.) What is the oxidation number for iron (II) in iron (II) oxide? 18. Write the names for the compound FeO and Fe2O3. Justify why the names you wrote are correct. 19.) What are the seven diatomic elements? 20.) What is the name of the compound Si2Br6? 21.) Write the formula for diboron hexahydride. 22.) Write the formula for oxygen gas.

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