elements around us

[مستر محمد طلعت]

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image001.gif[/IMG]Elements around us

Activity: To know the constituents of matter.

Examine some substances such as:

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image002.gif[/IMG]-Nails Made of iron.

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image003.gif[/IMG]- Spoon Aluminium.

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image002.gif[/IMG]- Electric wires Copper.

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image004.gif[/IMG]- Coal Carbon.

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image005.gif[/IMG]- Sulphur crystals Sulpher.

Conclusion: matter is composed of elements.

Element: It is the building unit of matter and it is the simplest form of matter that can't be ****yzed into two substances or more.

Scientists classified the elements into:

1-Metals:

-Solids as Iron, Copper, Aluminum, Gold, Silver and lead.

- Liquids as Mercury.

2-Non-metals:

- Solids as Sulphur, Carbon, Phosphorus.

- Liquids as Bromine.

- Gasesas Oxygen, Nitrogen.

Notes:

1. The molecules and atoms of an element are different from molecules of another element.

2. The element consists of two similar atoms

3. They are not decomposed to simplest substances by chemical or physical means.

4. They are split up under certain condition by (nuclear fission).

5. The scientists have discovered 112 elements

a) 92 are found in nature.

b) The rest (20) are synthesized under certain conditions

Properties of metals and non-metals:

1. Metals are shiny (have metallic luster) but non-metals are not.

2. Metals are good conductors of electricity but non-metals are bad conductors of electricity except carbon.

3. Metals are good conductors of heat while non-metals are bad conductors of heat.

4. Metals have high boiling and melting points but non-metals have low boiling and melting points.

5. Metals are malleable but non-metals are not.

Activity: To prove the shining property of metals.

Steps

Observation

Conclusion

1- Bring samples of different elements such as: Iron nail, copper wire, aluminum wire, Sulphur, mercury, coal.

2- Examine which of them is shiny and which is not shiny

1- Iron nail, copper wire, mercury and aluminum are shiny.

2- Coal and Sulphur are not shiny.

Metals are shiny but non-metals are not shiny.

Activity: To prove the ability of metals and non-metals to conduct electricity.

Steps

Observation

Conclusion

1- Bring a dry cell, an electric lamp and a copper wire.

From an electric circuit fig (A)

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image007.jpg[/IMG]

The electric lamp lights

1- Metals are good conductors of electricity

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image009.jpg[/IMG]Connect an iron with end of a copper wire fig (.

The electric lamp lights

[IMG]file:///C:\Users\ziad\AppData\Local\Temp\OICE_D05BDB0F-ED2A-4300-82AE-BC02F43AC27F.0\msohtmlclip1\01\clip_image011.jpg[/IMG]Repeat the previous step replacing an iron nail with a graphite rod once and Sulphur another time.

The electric lamp lights in case of graphite but not in Sulphur

2- Non-metals are bad conductors of electricity except carbon