Post on 22-Feb-2016
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Ionic Compounds
Lewis Dot DiagramsChemical Interactions Occur between
the Valence Electrons
Dots: represent valence electrons
When atoms combine to make molecules, they form chemical bonds.
Valence electron interaction
Forming Chemical Bonds
• Octet Rule Atoms will form bonds by: – Sharing– Giving or – Takingelectrons to complete their octet
Higher energy farther away from nucleus
Atoms form ions to have stable electron configurations (similar
to noble gases)
hh
Ionic Bonds
• Ionic Bonds form when one atom (nonmetal) gains electrons and the other atom (metal) loses electrons in order to gain stability.
• Ionic Bonds form between a metal (cation) and a nonmetal (anion).
To form an ion, lithium will most likely:
1 2 3 4
5% 5%
91%
0%
1. Gain 1 electron2. Gain 2 electrons3. Lose 1 electron4. Lose 2 electrons
Forming Chemical Bonds• Lithium
–Better to lose 1 electron or to gain 7
electrons?
X
Therefore, as an ion lithium will have what charge?
1 2 3 4
73%
0%
27%
0%
1. 1+2. 2+3. 1-4. 2-
Ionic Bonds • Atoms gain or lose its electrons
+
NaCl - salt
Chemical Interactions Occur between the Valence Electrons
Lewis structures are simpler to do & see
Formation of MgCl2
Formation of Na2S
• Write down the chemical formula for Aluminum Flouride
Formation of AlF3
Today is a practice Day!
• We need to be able to name ions given chemical formula
• We need to be able to determine the chemical formula given the name
Valence Electrons Noble Gas Structure = Octet
1,2 3,4,5,6,7,8
IONIC BONDS / Cations and Anions
Cation – positive ionsTransition Metals use
Roman Numerals to tell you the ox # Anion – negative ions
Oxidation Numbers
• Oxidation Numbers- indicated # of e’ lost, gained or shared.
Ex. Oxidation number of chlorine is -1
Halogens will have an oxidation number of:
1 2 -1 -2
0% 0%0%0%
1. +12. +23. -14. -2
Alkaline earth metals will have an oxidation number of:
1 2 -1 -2
0% 0%0%0%
1. +12. +23. -14. -2
We will name binary compounds together
• Using pages 156- 158• Describe how to name cations
and anions when they are by themselves
Naming Binary Ionic Compounds
• Write the name of the ionic compound, Ca2N3.
• Write the name of the ionic compound, K2O.
What is the name of BeBr2?
Boron bro
mine
Beryllium bro
m...
Bromide beryll...
Beryllium bro
m...
Beryllide brom...
0% 0% 0%0%0%
1. Boron bromine2. Beryllium bromine3. Bromide beryllide4. Beryllium bromide5. Beryllide bromide
Metals with Variable Charges
• Many transition metals can form more than one type of cation.
• For this reason, you must show the oxidation number in the name using Roman Numerals
Naming Binary Ionic Compounds with Transition
Metal Cations• Write the name of
the ionic compound, Cu2O..
• Write the name of the ionic compound, NiS.
What is the name for SnBr2?
Bromide Tin
Tin Bromide
Tin (I) Bromid...
Tin (II) B
romi...
Tin (III) B
rom...
Tin (IV) B
romi...
0% 0% 0%0%0%0%
1. Bromide Tin2. Tin Bromide3. Tin (I) Bromide4. Tin (II) Bromide5. Tin (III) Bromide6. Tin (IV) Bromide
What is the name for FeI3?
Iron io
dide
Iron (I)
iodid...
Iron (II
) iodi...
Iron (II
I) iod...
0% 0%0%0%
1. Iron iodide2. Iron (I) iodide3. Iron (II) iodide4. Iron (III) iodide
What is the name for MnS?
Manganese
sulf..
.
Manganese
(I) ...
Manganese
(II)...
Manganese
(III...
0% 0%0%0%
1. Manganese sulfide2. Manganese (I) sulfide3. Manganese (II) sulfide4. Manganese (III) sulfide
Exceptions:• Some of the transition metals
have only one ionic charge:–Do not need to use roman
numerals for these:–Silver is always 1+ (Ag1+)–Cadmium and Zinc are always
2+ (Cd2+ and Zn2+)
Writing Formulas for Binary Ionic Compounds
• Write the formula for barium iodide.
• Write the formula for sodium oxide.
• Write the formula for aluminum nitride.
• Write the formula for copper (I) sulfide.
Criss-Cross Method for Writing Formulas
- You can write the oxidationnumber and criss-cross them as subscripts.
- Note – if not in lowest termsyou must reduce the subscripts(ex. Magnesium oxide)
Al3+ S2-2 3
= Al2S3
What is the formula for aluminum bromide?
AlBr AlBr2
Al3Br Br3Al
AlBr3
0% 0% 0%0%0%
1. AlBr2. AlBr2
3. Al3Br4. Br3Al5. AlBr3
What is the formula for magnesium oxide?
MgO
Mg2
O2
MgO
2 M
g2O
OMg
0% 0% 0%0%0%
1. MgO2. Mg2O2
3. MgO2
4. Mg2O5. OMg
Write the formula for titanium (II) chloride.
TiCl Ti2Cl
TiCl2 Ti2Cl2
0% 0%0%0%
1. TiCl2. Ti2Cl3. TiCl24. Ti2Cl2
Write the formula for tin (IV) oxide.
SnO
SnO4
SnO2
Sn4O
Sn2O
0% 0% 0%0%0%
1. SnO2. SnO4
3. SnO2
4. Sn4O5. Sn2O
POLYATOMIC IONS• Not all compounds are made of only 2
types of atoms• poly – “many”
Memorize the polyatomic ions from p. 170.
Tricks for Polyatomic Naming
Perchlorate per+root+ate ClO4-1
chlorate root+ate ClO3-1
chlorite root+ite ClO2-1
Hypochlorite hypo+root+ite ClO-1
Prefixes and suffixes designate number of oxygens
Naming Polyatomic Ionic Compounds
• Polyatomic ionic compounds are named just like binary ionic compounds.
• Exception: be sure to enclose the polyatomic ion in parentheses before writing the subscript (only necessary if subscript is not 1).
• Ex. Barium hydroxide = Ba(OH)2
Write the formula for Calcium Nitrate.
CaNO2
Ca(NO2)2
Ca2NO3
Ca2NO2
Ca(NO3)2
0% 0% 0%0%0%
1. CaNO2
2. Ca(NO2)2
3. Ca2NO3
4. Ca2NO2
5. Ca(NO3)2
Write the formula for Magnesium Phosphate.
MgP
O4
Mg3
(PO4)2
Mg4
(PO3)2
MgP
O3
Mg(P
O4)2
0% 0% 0%0%0%
1. MgPO4
2. Mg3(PO4)2
3. Mg4(PO3)2
4. MgPO3
5. Mg(PO4)2
Naming Ionic Compounds