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Polyatomics

Polyatomics. Polyatomics. Remember that the smallest part of a compound is a molecule. Sometimes the bonds between certain atoms in a molecule are so strong that they do not dissociate when dissolved. i.e NH 4 OH This is ammonium hydroxide

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Polyatomics

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  1. Polyatomics

  2. Polyatomics • Remember that the smallest part of a compound is a molecule. • Sometimes the bonds between certain atoms in a molecule are so strong that they do not dissociate when dissolved. • i.e NH4OH This is ammonium hydroxide • When it dissolves in water it becomes the 2 polyatomic molecules (ions) • NH4+1 and OH-1 • Notice how the NH4 and the OH stay together when dissolved. • They are the polyatomic molecules that make up ammonium hydroxide

  3. Ionic Compounds are two or more elements that are held together by opposite charge attraction. IONIC COMPOUNDS Oxygen-8 Magnesium-12 -2 Charge +2 Charge Metal Non-metal

  4. Metals combine with non-metals Metals lose electrons to non-metals They then attract because their charges will be opposite. Metals

  5. Negative Ions (single atoms) -2 -1 -3 Most of the negative ions have a set negative charge

  6. POLYATOMIC IONS (charged building blocks)Polyatomic ions are ions that consist of more than 1 atom. So they are groups of 2 or more atoms that act as one. • Eg. Sulfate SO4-2 4 oxygen atoms, 1 sulfur atom, with a charge of -2

  7. POLYATOMIC IONS Polyatomic ions are mostly made of two non-metals. Ions with -1 charge perbromate BrO4-1 bromate BrO3-1 bromite BrO2-1 hypobromite BrO-1 perchlorate ClO4-1 chlorate ClO3-1 chlorite ClO2-1 hypochlorite ClO-1 periodate IO4-1 iodate IO3-1 iodite IO2-1 hypoiodite IO-1 nitrate NO3-1 nitrite NO2-1 hydroxide OH-1 cyanide CN-1 acetate C2H3O2-1 Permanganate MnO4-1 bicarbonate HCO3-1 Ions with a -2 Charge carbonate CO3-2 sulfate SO4-2 sulfite SO3-2 chromate CrO4-2 dichromate Cr2O7-2 oxalate C2O4-2 Ions with a -3 Charge phosphate PO4-3 phosphite PO3-3 arsenate AsO4-3 Ions with +1 charge ammonium ion NH4+1

  8. These polyatomic ions have the same charge as these single elements -1 Ions with -1 charge perbromate BrO4-1 bromate BrO3-1 bromite BrO2-1 hypobromite BrO-1 perchlorate ClO4-1 chlorate ClO3-1 chlorite ClO2-1 hypochlorite ClO-1 periodate IO4-1 iodate IO3-1 iodite IO2-1 hypoiodite IO-1

  9. These polyatomic ions have the same charge as these single elements Ions with a -2 Charge sulfate SO4-2sulfite SO3-2 Ions with a -3 Charge phosphate PO4-3 phosphite PO3-3 -3 -2

  10. Naming Ionic Compounds Cu2SO4 Cu2+xSO4-2 2x +1(-2)=0 x = +1 Ionic compounds are made of two ions. One positive and the other negative. The positive ion (usually a metal or ammonium) is named first while the negative ion (a non-metal or a polyatomic ion) is named last. The charge on the negative ion is used to determine the charge on the positive ion that has multiple ionic states General formula (only use this when the positive ion has multiple charges): subscript(charge) + subscript(charge) = 0 Copper (I) Sulfate Ion # 2 Ion # 1

  11. If the ionic compound is binary (2 atoms), the name of the negative ion will end in “-ide”. If the negative ion is a polyatomic ion the compound is no longer binary. The ending will be that carried by the polyatomic ion. These endings are either “-ate” or “-ite.”

  12. Examples #2- Formulas to Names 1. Write the names of the ions 2. Determine the charge of the positive ion NH4NO3 I’m a polyatomic ion ammonium nitrate Final Name If the positive ion has a fixed charge, you are finished.

  13. Examples #4- Formulas to Names 1. Write the names of the ions 2. Determine the charge of the positive ion Cu2S X = +1 2(X) + 1(-2) = 0 Cu2x(S)-2= 0 I’m not a polyatomic ion copper sulfide (I) Final Name

  14. Examples #1- Formulas to Names 1. Write the names of the ions = 0 -2 CuSO3 2. Determine the charge of the positive ion Cu +2 SO3 x 1(X )+ 1(- 2) = 0 Hi! I’m a polyatomic ion You must know the charge on the sulfite ion is -2 The sum of the positive and negative charges must equal zero +2 = +2 X = +2 copper sulfite (II) Final Name Next

  15. Examples #1- Formulas to Names 1. Write the names of the ions = 0 -2 Fe2(SO4)3 2. Determine the charge of the positive ion Fe2 (SO4)3 +3 x 2(X )+ 3(- 2) = 0 Hi! I’m a polyatomic ion You must know the charge on the sulfite ion is -2 The sum of the positive and negative charges must equal zero 2x - 6 = 0 + 6 = +6 2x = 6 2 2 X = +3 Iron sulfate (III) Final Name Next

  16. Practice Problem #1 Fe(NO3)3 Choose the correct name for the compound 1. Iron trinitrate No, you do not use prefixes 2. iron(I) nitrate No, you have the wrong oxidation number 3. iron(III) nitrite No, you need to review polyatomic ions 4. iron(III) nitrate Very good, click arrow to continue 5. none of the above No, there is a correct answer nextproblem Periodic Chart Polyatomic Ions

  17. Practice Problem #2 sodium chlorite Choose the correct formula for the compound 1. NaCl No, you need to review prefixes 2.NaClO No, you need to review prefixes Very good, click arrow to continue 3. NaClO2 No, you have several errors 4. Na(ClO)2 No, there is a correct answer 5. none of the above nextproblem Prefixes Periodic Chart

  18. Properties of Ionic Compounds • Hard and brittle solids • High melting points • Highly soluble in water- electrolyte • Are good conductors of electricity in solution

  19. Solubility • The ability of a solid to dissolve in liquid Ionic compounds have high solubility

  20. Conductivity • Ability of a substance to conduct electricity Electrolyte: A solution that contains Dissolved Ions that conduct electricity

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