C5: Ionic and Molecular
Compounds
C5 Vocabulary terms to define:
Allotrope
Hygroscopic
Anhydrous
Inorganic compound
Binary compound
Molecular element
Deliquescent
Molecular substance
Distillation
Organic compound
Formula unit
Oxidation number
Hydrate
Polyatomic ion
Hydrocarbon
C5 Vocabulary Quiz
Definitions:
Word Bank:
1. A compound that only contains two
elements.
2. The charge on the ion.
3. An ion group that has two or more
different elements. Ie: SO4-2, aka
sulfate.
4. A substance that absorbs enough
water to become a liquid solution.
5. A compound with all the water
removed.
6. A compound held together by a
covalent bond
7. A transfer of electrons resulting in a
this type of bond.
8. Molecules of the same element with
different structure.
Ionic bond
Molecular substance
Oxidation number
Formula unit
Distillation
Allotrope
Anhydrous
Binary compound
Polyatomic ion
Hygroscopic
5.1: Ionic Compounds
• Review of common properties:
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Transfer of electrons to make ions
Electrostatic attraction (opposite charges attract)
Brittle
Conduct electricity when dissolved in water or molten
Strong Bond
– High melting points
Binary Ionic Compounds
• Binary = A compound that contains only two
elements.
• Examples
– KI = potassium iodide
– NaCl = sodium chloride
Naming Binary Ionic Compounds
• Steps:
– 1. Write the name of the positively charged ion.
• Usually a metal. Example: Na = Sodium
– 2. Add the name of the negatively charged ion.
• Usually a nonmetal. Example: Chlorine
– 3. Change the ending to –ide
• Example: Chlorine becomes Chloride
Practice Naming Binary
Compounds
Use your periodic table to name the following:
1.KI
2.KCl
3. CaS
4.NaBr
5.BaO
Predicting Charge on Ions
Using Charges to write formulas
• Oxidation number = charge on ion.
• Charges must cancel (equal and opposite for
compounds to form)
Practice:
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1. lithium oxide
2. calcium bromide
3. sodium oxide
4. aluminum sulfide
Polyatomic ions
Poly = “many”
Polyatomic ion = an ion that has two or more
different elements.
Writing a formula containing a
polyatomic ion
• Write the formula for lithium carbonate
1. Find group and charge of lithium using periodic
table.
2. Look at polyatomic table and find carbonate.
3. Write the symbols for lithium and carbonate.
4. Determine the correct ratios to cancel charges
5. Check your work
Examples and practice
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Sodium phosphate
Magnesium hydroxide
Ammonium phosphate
Potassium dichromate
Aluminum sulfate
Compounds with Transition metals
• C3 we learned Transition metals are not as
predictable as representative elements (main
group)
• Sometimes Transition metals can have more
than one charge depending on reaction
conditions
• We identify the specific charge using Roman
Numerals!
Examples
• Iron(III) sulfate = Fe2(SO4)3
• Copper(II) oxide = CuO
Practice
• Write the formula for the following:
– Copper(I) sulfite
– Tin(IV) fluoride
– Gold(III) cyanide
• Write the names for the following:
– Pb(NO3)2
– Mn2O3
– HgF2
Hydrates and Anhydrous
Compounds
C5-2: Molecular Substances
• Substances held together by covalent bonds
– Covalent = electrons are shared
• Examples of molecular substances:
– plastics
– Fats, oils etc…
– Rubber
– Diamond and quartz
Properties of molecular substances
• Varied properties…soft, elastic, to hard.
• Distillation = a method of separating
substances in a mixture by evaporation of a
liquid and condensing the vapor.
Molecular Elements
• Meet Mr. BrINClHOF
• Diatomics
– Br2, I2, N2, Cl2, H2, O2, F2
Allotropes
• Molecules of a single element that differ in
structure.
• Example:
Naming Molecular Compounds
• Name first element (farthest left element on
periodic table). Use a prefix if there is more
than one.
• Name the second element and use a prefix to
denote the number of elements in compound.
Change the ending to –ide.
Prefixes
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Mono = 1
Di = 2
Tri = 3
Tetra = 4
Penta = 5
Hexa = 6
Hepta = 7
Octa = 9
Nona = 9
Deca = 10
Examples
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CO2 = carbon dioxide
CO = carbon monoxide
N2O3 = dinitrogen trioxide
CS2 = carbon disulfide
Practice
• Name the following molecular substances:
– S2Cl2
– SO3
– P4O10
• Write the formula for the following molecular
substances:
– Carbon tetrachloride
– Iodine heptafluoride
– Sulfur dioxide
C5-1 Summary
• Binary ionic compounds: naming and writing
formulas
• Position on periodic table determines charge
• Polyatomic ions – use the table
• Transition metals use Roman Numerals
• Hydrates v. anhydrous
C5-2 Summary
• Molecular substances: naming and writing
formulas
• Seven diatomics: BrINClHOF
• Allotropes