Chapter 6
Download
1 / 19

Chapter 6 - PowerPoint PPT Presentation


  • 98 Views
  • Uploaded on

Chapter 6. Metals. Why is all of this stuff important?. Properties of elements determine what we can use them for. For example, tungsten has the highest melting point of any metal (3410 0 C) but it is very ductile. For these reasons we use it in light bulbs as the filament. . Metal Atoms.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Chapter 6' - ivria


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chapter 6

Chapter 6

Metals


Why is all of this stuff important
Why is all of this stuff important?

Properties of elements determine what we can use them for.

For example, tungsten has the highest melting point of any metal (34100C) but it is very ductile. For these reasons we use it in light bulbs as the filament.


Metal atoms
Metal Atoms

Metal atoms lose electrons to become stable.

If there is a nonmetal around to bond with, they will give it their electrons and become part of a stable compound.


Metallic bonds
Metallic Bonds

If there is not a nonmetal around, they have another solution.

They become cations with free electrons floating around them.

A metallic bond is the attraction between the cation and the free electrons around it.


Metallic bonds1
Metallic Bonds

The cations in a metal form a lattice (like the lines on graph paper) that is held in place by strong metallic bonds between the cations and the surrounding valence electrons.

Because the total number of electrons does not change, the total metal is neutral.


Metallic bonds2
Metallic Bonds

Metallic bonds in some metals are stronger than in other metals.

The more valence electrons in the shared pool, the stronger the metal will be.

Alkali metals can only contribute 1 electron each to the pool so they are weak.

Transition metals contribute more electrons so they are stronger.


Remember
Remember

The stronger the metal, the higher its boiling point.


Metal properties
Metal Properties

Metals’ properties are caused by the movement of electrons within the metal lattice.


Conductivity
Conductivity

Metals conduct electric current.

Electric current is a flow of charged particles.

The pool of shared electrons in metals act like a reservoir for electric current to pass through.


Malleability
Malleability

Malleability is flexibility.

The metal lattice is flexible compared to a rigid ionic compound lattice (remember those shatter when struck).

When a metal lattice (a piece of metal) is struck, the ions shift slightly but do not break their metallic bonds.

For this same reason, metals are ductile.


Alloys
Alloys

Alloys are mixtures of 2 or more elements (at least 1 of the elements must be a metal).

Alloys have the properties of metals.


Types of alloys
Types of Alloys

Copper alloys

Steel alloys

Others


Copper alloys
Copper Alloys

Copper alone is a soft metal.

Bronze = copper and tin

Bronze is hard and durable.

Brass = copper and zinc

Brass is softer and shinier than bronze but not as durable.


Steel alloys
Steel Alloys

Steel = iron + carbon

Carbon atoms fill in spaces in the iron lattice and add strength.

Stainless steel = iron + chromium

The chromium keeps the steel from rusting, but stainless steel is more brittle than steel containing carbon.

Other steels contain sulfur, manganese, phosphorus, and/or silicon.


Other alloys
Other Alloys

Alloys can be made to suit different needs based on what elements are added to them.


Why alloys
Why Alloys?

Pure gold (24 karat) is easily worn and bent.

Adding silver, copper, nickel, or zinc to gold (and reducing its karat or purity) makes it stronger and more durable.


Why alloys1
Why Alloys?

Aluminum is light but weak.

When copper or manganese are added to aluminum it gains strength without gaining excessive weight.

This is used to build airplane bodies.


Why alloys2
Why Alloys?

Magnesium burns when exposed to air.

An aluminum-magnesium alloy stabilizes magnesium.

This compound is used to make very lightweight airplane parts.


Why alloys3
Why Alloys?

Bridge cables need to resist stretching and pulling while supporting a great amount of weight.

Special steel alloys are used for this.


ad