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

variable

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

Normal Ion Charges

Octet Rule –

Atoms will gain or lose electrons to have 8 valence electrons.

Ionic bonds are formed by electron transfer between a metal & a nonmetal)

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.

PRACTICE:

#1-9 (p. 199)

&

#10-19 p. 203, 207)

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

Chapter 7 ASSIGNMENTChapter 7

Chapter 7 #27-44 (p. 214)