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THE PERIODIC TABLE . The rows across the elements in the periodic table are called periodsThe columns down are called groups.The groups are numbered from 1 to 8Group 8 is also called group 0.. SOME GROUPS. Group 1 are found on the far left side and are called the alkali metalsGroup 7 are foun
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1. THE PERIODIC TABLE Objectives
To be able to identify groups and periods in the periodic table
To know the positions of group1, group 0 and group 7 in the periodic table
To know the positions, properties and uses of the halogens
Read through the slides and then complete the linked worksheets
2. THE PERIODIC TABLE The rows across the elements in the periodic table are called periods
The columns down are called groups.
The groups are numbered from 1 to 8
Group 8 is also called group 0.
3. SOME GROUPS
Group 1 are found on the far left side and are called the alkali metals
Group 7 are found at the right hand side and are called the halogens.
Group 8 are also known as group 0 and are called the noble gases
4. GROUP 7 These elements are all non- metals.
They are also called the halogens
They are:-
Fluorine
Chlorine
Bromine
Iodine
5. They have low melting points (this means that the change from a solid to a liquid at a low temperature)
They do not conduct electricity
They go around as pairs of atoms.
We call them diatomic molecules
We write them like this
Fluorine - F2
Chlorine - Cl2
Bromine - Br2
Iodine - I2
6. What are they like? Fluorine is a very pale yellow gas
Chlorine is a green gas
Bromine is a dark red brown liquid
Iodine is a black shiny solid
7. THE REACTIONS OF THE HALOGENS The halogens like to take part in chemical reactions
The react with metals to make salts
The most reactive halogen is fluorine and the least reactive is iodine.
They get less reactive as you go down the group most
reactive
Least
reactive
8. Uses of the halogens Iodine is used as an antiseptic
Chlorine is used in swimming pools to kill bacteria
Fluorine is used in tooth paste
Bromine is used photographic film
9. Click here and complete the worksheetClick here to complete the reactions of the halogens
10. Click here to go to part 3