chapter 4 part 1 - ionic compounds electron review l valence electrons - electrons in the outer...
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Chapter 4Chapter 4
Part 1 - Ionic Compounds
Electron Review
Valence electrons - electrons in the outer energy level.
Core electrons -those in the energy levels below.
Electron Review
Which type of electron is responsible for bonding? Why?
Electron/Periodic Table Review Atoms in the same column:
–Have the same outer electron configuration.
–Have the same valence electrons.
–Easily found by looking up the group number on the periodic table.
Electron/Periodic Table Review
Group 2A
How many Valence Electrons?
Group 8A
How many Valence Electrons?
Noble Gas Configuration
Q: What’s so special about 8 electrons?
A: STABILITY!
Noble Gas Configuration
All atoms seek to achieve the same stability of a noble gas by gaining, losing, or sharing electrons with another atom.
HOW?
Noble Gas Configuration
THROUGH BONDING!• Ionic bonding
• Covalent bonding
Review Question
Group 1A and 2A are what type of element?
(metal, nonmetal, metalloid)
MetalsMetals lose electrons to attain
noble gas configuration.They make positive ions
called cations.
Electron Dots For Cations
Metals will have few valence electrons
Ca
Electron Dots For Cations Metals will have few valence electrons These will come off
Ca
Electron Dots For Cations Metals will have few valence electrons These will lose electrons Form positive ions
Ca2+
Review Question
Group 5A elements are mostly what type of element?
(metal, nonmetal, metalloid)
Nonmetals
Nonmetals gain electrons to attain noble gas configuration.
They make negative ions called anions
Electron Dots For Anions Nonmetals will have many valence
electrons. They will gain electrons to fill outer shell.
P P3-
Noble Gas Configurations All atoms react to achieve noble gas
configuration. Noble gases have 8 valence
electrons Also called the octet rule.
Ar
Ionic BondingAnions and cations are held
together by opposite charges.These are called ionic
compoundsIonic compounds are also
called salts.
Ionic Bonding The bond is formed through the transfer of electrons.
Electrons are transferred to achieve noble gas configuration by both metal and nonmetal.
Ionic Bonding
Na Cl
Ionic Bonding
Na+ Cl-
Ionic Bonding All the electrons must be accounted for!
Ca P
Ionic Bonding
Ca P
Ionic Bonding
Ca+2 P
Ionic Bonding
Ca+2 P
Ca
Ionic Bonding
Ca+2 P-3
Ca
Ionic Bonding
Ca+2 P-3
Ca P
Ionic Bonding
Ca+2 P-3
Ca+2 P
Ionic Bonding
Ca+2 P-3
Ca+2 P
Ca
Ionic Bonding
Ca+2 P-3
Ca+2 P
Ca
Ionic Bonding
Ca+2 P-3
Ca+2P
-3
Ca+2
Ionic Bonding
Ca3P2
Ionic Compound
Properties of Ionic Compounds Crystalline structure. A regular repeating arrangement of ions
in the solid. Ions are strongly bonded. Structure is rigid. High melting points- because of strong
forces between ions.
Crystalline structure
Do they Conduct? Conducting electricity is allowing charges
to move. In a solid, the ions are locked in place. Ionic solids are insulators. When melted, the ions can move around. Melted ionic compounds conduct. Have to get them to 800ºC. Dissolved in water they conduct –
electrons are free to move.
Ionic solids are brittle
+ - + -+- +-
+ - + -+- +-
Ionic solids are brittle
+ - + -
+- +-+ - + -
+- +-
Strong Repulsion breaks crystal apart.
Metallic Bonds How atoms are held together in a metal
solid. Metals hold onto there valence
electrons very weakly. Think of them as positive ions floating in
a sea of electrons. Electrons are free to move from atom to
atom. Electrons moving = electricity!!!
Sea of Electrons
+ + + ++ + + +
+ + + +
Electrons are free to move through the solid.
Metals conduct electricity.
Metals are:Malleable - Hammered
into shape (bend).
Ductile - drawn into wires.
Malleable
+ + + ++ + + +
+ + + +
Malleable
+ + + +
+ + + ++ + + +
Electrons allow atoms to slide by.