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Chapter 7Chapter 7
Ionic & Metallic BondingIonic & Metallic Bonding
Anything in black letters = write it in your notes (‘knowts’)
Valence Electrons & Ion Formation
valence electrons
electron dot (Lewis) structures
cations & anions
octet rule
Ionic & Metallic Bonding
ionic compounds (properties)
formula units
alloys
Chapter 6 Objectives
Electron Dot Diagrams – valence electrons as dots around chemical symbol
These are also known as Lewis Symbols
3 Main Rules for Lewis Symbols
2. Fill all 4 sides before pairing.
C ●
1. No more than 2 dots on each side.
3. No more than 8 dots total.
●
C
C●●●
● C●●●●
●●
●●
●
●
wrong wrong
wrongCorrect!
Na Mg Al Si P S Cl Ar
Draw Lewis Symbols for these elements
1. Fill all 4 sides before pairing.
2. No more than 2 dots on each side.
3. No more than 8 dots total.
Metal atoms lose their valence electrons easily.
Nonmetal atoms gain electrons to fill their valence to 8.
REMEMBER!!
If an atom gains an electron, it becomes a -1 ion
If an atom loses an electron, it becomes a +1 ion
Ca+ion = positive ion
Anion = negative ion
Ionic compounds consist of cations and anions arranged in repeating patterns; NOT as discrete units like molecules
A formula unit is the lowest ratio of ions in an ionic compound.
Properties of Ionic Compounds
High melting points
Crystalline solids at room temperature
Conduct electric current when molten or dissolved in water.
The valence electrons in metals are loosely held and are free to move.
The properties of metals can be explained by the ‘sea of electrons’ model.
7.3 – Bonding in Metals7.3 – Bonding in Metals
Alloy – mixture of metals.
Steel –
Stainless Steel –
Bronze –
Solder –
Brass –
Sterling Silver –
Amalgam –
Nichrome –
Alloy – mixture of metals.
Steel – Fe & C
Stainless Steel – steel w/ Cr, Ni, or Mn
Bronze – Cu & Sn
Solder – Sn & Pb
Brass – Cu & Zn
Sterling Silver – Ag & usually Cu
Amalgam – Hg w/ other metals (Ag, Sn, Cu)
Nichrome – Ni & Cr