IONIC COMPOUNDS. STABILITY Relates to nobility Every element’s dream They’ll do what they can to...
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Transcript of IONIC COMPOUNDS. STABILITY Relates to nobility Every element’s dream They’ll do what they can to...
IONIC COMPOUNDS
STABILITY• Relates to nobility• Every element’s dream• They’ll do what they can to
look like a noble gas…pseudo-noble gas configuration
• Duet Rule• Octet Rule• Potential Energy
Bond Energy• The energy required to break a bond• The energy is absorbed when the
bond is broken, thus…released when formed
• Stronger bonds are more stable– Require more energy to break them– i.e. ionic bonds
• Weaker bonds are less stable– Require less energy to break them– i.e. molecular or covalent bonds
Achieving Stability• Ionic bonds made by transferring
electrons• Metals will do what?
• Nonmetals will do what?
• Once electrons are transferred, the atoms are converted to ions.
lose electron(s)
gain electron(s)
Ions• Positively charged ions are called?
• Negatively charged ions are called?
• Bond to make an ionic compound or salt
cations
anions
Salts• Made of metals and nonmetals or
polyatomic ions• Solid
– Ordered arrangement called crystal lattice
• Brittle• High melting point• Electrical conductors in aqueous
and molten phases
More About Ions• Written as a symbol with superscript
to the right indicating the charge• Charge is written as a number
followed by a + or – sign• Monatomic ions—”one-atomed” ions• Polyatomic ions—”many-atomed” ions
Monatomic Ions• Use periodic table to determine
charges of representative elements• Group 1…1+…element name + ion• Group 2…2+…element name + ion• Group 13…3+…element name +
ion• Group 14…skip• Group 15…3-…ide ending + ion• Group 16…2-…ide ending + ion• Group 17…1-…ide ending + ion
Monatomic Ions• For the transition metals, you must
memorize the possible charges of the common ionsCr2+ Chromium (II) ion Chromous ion
Cr3+ Chromium (III) ion
Chromic ion
Mn2+ Manganese (II) ion
Manganous ion
Mn3+ Manganese (III) ion
Manganic ion
Fe2+ Iron (II) ion Ferrous ion
Fe3+ Iron (III) ion Ferric ion
Monatomic IonsCo2+ Cobalt (II) ion Cobaltous ion
Co3+ Cobalt (III) ion Cobaltic ion
Ni2+ Nickel (II) ion Nickelous ion
Ni3+ Nickel (III) ion Nickelic ion
Cu1+ Copper (I) ion Cuprous ion
Cu2+ Copper (II) ion Cupric ion
Hg22
+
Mercury (I) ion Mercurous ion
Hg2+ Mercury (II) ion Mercuric ion
Monatomic IonsSn2+ Tin (II) ion Stannous ion
Sn4+ Tin (IV) ion Stannic ion
Pb2+ Lead (II) ion Plumbous ion
Pb4+ Lead (IV) ion Plumbic ion
Ag1+ Silver ion
Zn2+ Zinc ion
Cd2+ Cadmium ion
Polyatomic Ions• Refer to handout• Know the formula (that means
elements, subscripts, and charge) of each listed
Making Ionic Compounds
• A cation and an anion will bond in order to bring the charge of the compound to zero.
• A “criss-cross” method is used to determine the number of each ion necessary to balance the charges
• Always reduce subscripts.
Making Ionic Compounds
Na1+Cl1-1 1
= NaCl
= MgCl2= AlCl3
Mg2+Cl1-1 2
Al3+ Cl1-1 3
Making Ionic Compounds
NaCl
MgCl2
AlCl3
sodium chloride
magnesium chloridealuminum chloride
Making Ionic Compounds
Na1+ S 2-2 1
= Na2S
= MgO
= Ca3P2
Mg2+O 2-2 2
Ca2+P 3-3 2
Making Ionic Compounds
Na2S
MgO
Ca3P2
sodium sulfide
magnesium oxide
calcium phosphide
Making Ionic Compounds
Pb4+ O 2-2 4
= PbO2
= AgI
= Fe2O3
Ag1+I 1-1 1
Fe3+O 2-2 3
Making Ionic Compounds
PbO2
AgI
Fe2O3iron (III) oxide orferric oxide
silver iodide
Lead (IV) oxide orplumbic oxide
Making Ionic Compounds
Pb4+ (OH)1-1 4
= Pb(OH)4
= MgSO4
= Al2(C2O4)3
Mg2+(SO4)2-2 2
Al3+(C2O4)2-2 3
Making Ionic Compounds
Pb(OH)4
MgSO4
Al2(C2O4)3
lead (IV) hydroxide orplumbic hydroxidemagnesium sulfate
aluminum oxalate
Crystal Lattice• 3-dimensional arrangement of
atoms or ions in a solid• Simplest part is called a unit cell• There are six types of crystal
systems– We will focus on the cubic unit cell
Cubic Unit Cells• Three types:
– Simple– Body-centered– Face-centered
Simple Cubic Unit
Cell
P
Face-centered Cubic Unit Cell
NaCl
Cl- ions
Na+ ions
Body-centered Cubic Unit Cell
CsClCs+ ion
Cl- ion
Now…•PRACTICE•PRACTICE•PRACTICE