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Ionic and Covalent Nomenclature

Naming Compounds Writing Formulas. Ionic and Covalent Nomenclature . Systematic Naming. There are more than 50 million named chemical substances Who thinks up the names for all these chemicals? Are we in danger of running out of new names?

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Ionic and Covalent Nomenclature

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  1. Naming Compounds Writing Formulas Ionic and Covalent Nomenclature

  2. Systematic Naming • There are more than 50 million named chemical substances • Who thinks up the names for all these chemicals? Are we in danger of running out of new names? • The answer to the last question is "no", for the simple reason that the vast majority of the names are not "thought up"; there are elaborate rules for assigning names to chemical substances on the basis of their structures.

  3. These are called systematic names; • they uniquely identify a given substance. • The rules for these names are defined by an international body. • every known chemical substance has its own numeric "personal ID", known as a CAS registry number. • For example, caffeine is uniquely identified by the registry number 58-08-2. About 12,000 new numbers are issued every day.

  4. Common Names • Many substances have common names that we use everyday • α-D-glucopyranosyl-(1,2)- β-D-fructofuranoside also known as table sugar or sucrose • Table salt Sodium chloride

  5. Some Common Substances • Borax sodium tetraborate decahydrate • Na2 B4O7·10H2O • calomel mercury(I) chloride • Hg2Cl2 • milk of magnesia magnesium hydroxide • Mg(OH)2 • muriatic acid hydrochloric acid • HCl(aq) • saltpeter sodium nitrate • NaNO3 • slaked lime calcium hydroxide • Ca(OH)2

  6. Compounds • Follow the Law of Definite Proportion. • Have a constant composition. • Same formula (atoms) every time • Two Major Types of Compounds • Ionic • Covalent or Molecular

  7. Molecular Compounds • Also called Covalent Compounds • Made of molecules • Made by joining nonmetal atoms together into molecules • Examples:

  8. Ionic Compounds • Made of cations and anions • Metals and nonmetals • The electrons lost by the cation are gained by the anion • The cation and anions surround each other • Smallest ratio of ions in an ionic compound is a FORMULA UNIT.

  9. Two Types of Compounds Ionic Molecular Smallest piece/ratio Formula Unit Molecule Types of elements Metal and Nonmetal Nonmetals Solid, liquid or gas State solid Melting Point High >300ºC Low <300ºC

  10. Cations • Positive ions • Formed by losing electrons • More protons than electrons • Metals usually K+1 Has lost one electron Ca+2 Has lost two electrons

  11. Anion • A negative ion • Has gained electrons • Non metals • Charge is written as a super script on the right. F-1 Has gained one electron O-2 Has gained two electrons

  12. Chemical Formulas • Shows the kind and number of atoms in the smallest piece of a substance. • Molecular formula- number and kinds of atoms in a molecule. • CO2 • C6H12O6

  13. Formula Unit • The smallest whole number ratio of atoms in an ionic compound. • Ions surround each other so you can’t say which is hooked to which

  14. Charges on ions • For Elements in Groups 1, 2,13-18 on the Periodic Table you can tell what kind of ion they will form from their location • Elements in the same group have similar properties • Including the charge when they are ions

  15. +1 +2 +3 -3 -2 -1

  16. What about the others? • We have to figure those out some other way. • More on this later.

  17. Naming Ions • We will use the systematic way • Cation- if the charge is always the same just write the name of the metal • Transition metals can have more than one type of charge • Indicate the charge with a Roman numeral in parentheses

  18. Name these • Na+1 • Ca+2 • Al+3 • Fe+3 • Fe+2 • Pb+2 • Li+1

  19. Write Formulas for these • Potassium ion • Magnesium ion • Copper (II) ion • Chromium (VI) ion • Barium ion • Mercury (II) ion

  20. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluorine

  21. Naming Anions • Anions are always the same. • Change the element ending to – ide • F-1 Fluoride

  22. Name these • Cl-1 • N-3 • Br-1 • O-2 • Ga+3

  23. Write these • Sulfide ion • iodide ion • phosphide ion • Strontium ion

  24. Polyatomic ions • Groups of atoms that stay together and have a charge • You must memorize these or use an ion sheet • Acetate C2H3O2-1 • Nitrate NO3-1 • Nitrite NO2-1 • Hydroxide OH-1 • Permanganate MnO4-1 • Cyanide CN-1

  25. Polyatomic ions • Sulfate SO4-2 • Sulfite SO3-2 • Carbonate CO3-2 • Chromate CrO4-2 • Dichromate Cr2O7-2 • Phosphate PO4-3 • Phosphite PO3-3 • Ammonium NH4+1

  26. Naming Ionic Compounds

  27. Binary Ionic Compounds • Binary Compounds • 2 elements. • a cation and an anion. • To write the names just name the two ions. • Easy with Representative elements • Groups 1, 2, 13 • NaCl = Na+ Cl- = sodium chloride • MgBr2 = Mg+2 Br- = magnesium bromide

  28. Naming Binary Ionic Compoundswith Variably Charged Cations • The problem comes with the transition metals (Groups 3-12) since their charge can vary • Need to figure out their charges • The compound must be neutral • same number of + and – charges. • Use the anion to determine the charge on the positive ion • Charge of the cation is a Roman numeral in the name

  29. Example • Write the name of CuO • Need the charge of Cu • O is -2 • copper must be +2 • Copper (II) chloride

  30. Example • Name CoCl3 • Cl is -1 and there are three of them = -3 • Co must be +3 Cobalt (III) chloride

  31. Another Example • Write the name of Cu2S. • Since S is -2, the Cu2 must be +2, so each one is +1. • copper (I) sulfide

  32. Last Example • Fe2O3 • Each O is -2 3 x -2 = -6 • 3 Fe must = +6, so each is +2. • iron (III) oxide

  33. Naming Binary Ionic Compounds • Write the names of the following • KCl • Na3N • CrN • Sc3P2 • PbO • PbO2 • Na2Se

  34. Ternary Ionic Compounds • Will have polyatomic ions • At least three elements • Name the ions • NaNO3 • CaSO4 • CuSO3 • (NH4)2O

  35. Ternary Ionic Compounds • LiCN • Fe(OH)3 • (NH4)2CO3 • NiPO4

  36. Writing FormulasGiven the name write the formula • The charges have to add up to zero • Write down each ion with charges • Make the charges equal by adding subscripts • Put polyatomic ions in parentheses

  37. Writing Formulas Example • Write the formula for calcium chloride. • Calcium is Ca+2 • Chloride is Cl-1 • Ca+2 Cl-1 would have a +1 charge. • Need another Cl-1 • Ca+2 Cl2-1

  38. Another Example • Aluminum nitrate

  39. Write the formulas for these • Lithium sulfide • tin (II) oxide • tin (IV) oxide • Magnesium fluoride • Copper (II) sulfate • Iron (III) phosphide

  40. Write the formulas for these • gallium nitrate • Iron (III) sulfide • Ammonium chloride • ammonium sulfide • barium nitrate

  41. Things to look for • If cation has (Roman Numeral), the number is their charge • If anions end in -ide they are probably off the periodic table (Monoatomic) • If anion ends in -ate or -ite it is polyatomic

  42. Writing names and Formulas Molecular Compounds

  43. Molecular compounds • made of just nonmetals • smallest piece is a molecule • can’t be held together because of opposite charges • can’t use charges to figure out how many of each atom

  44. Easier • Molecular compounds name tells you the number of atoms. • Uses prefixes to tell you the number

  45. Prefixes • 1 mono- • 2 di- • 3 tri- • 4 tetra- • 5 penta- • 6 hexa- • 7 hepta- • 8 octa-

  46. Prefixes • 9 nona- • 10 deca- • To write the name write two words

  47. Prefixes • 9 nona- • 10 deca- • To write the name write two words Prefix name Prefix name -ide

  48. Prefixes • 9 nona- • 10 deca- • To write the name write two words • One exception is we don’t write mono- if there is only one of the first element. Prefix name Prefix name -ide

  49. Prefixes • 9 nona- • 10 deca- • To write the name write two words • One exception is we don’t write mono- if there is only one of the first element. • No double vowels when writing names (oa oo) except with i Prefix name Prefix name -ide

  50. Name These • N2O • NO2 • Cl2O7 • CBr4 • CO2 • BaCl2

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