fun chemistry

halogens

2008-02-08T07:06:00.000-08:00

2008-02-08T06:43:00.000-08:00

The elements in Group 7 are called halogens. They belong to the column second from right in the periodic table.
The halogens are non-metals with molecules which each contain two atoms.
They have low melting points and boiling points,
They are poor conductors of heat and electricity.
They react with metals to make ionic compounds in which the halide ions have a -1 charge.

As you go down the group the halogens' melting and boiling points get higher, their colour becomes darker, and they become less reactive. A more-reactive halogen can displace a less-reactive halogen from its salt dissolved in water.

2008-02-08T06:29:00.000-08:00

2008-02-08T05:47:00.000-08:00

alkali metals :

The atoms of the elements in Group 1 all have one electron in their highest energy level,the outer shell,this is why their chemical propeties are similar.
When you write the electronic structure of an alkali metal, the last number must be a 1.
The alkali metals have low melting and boiling points compared to most other metals
The alkali metals are very soft.
Lithium is the hardest alkali metal and they become softer as you go down the group.
alkali metals become more reactive as you go down the group,
here is some examples of what happens to lithium,sodium and potassium react with water

lithium + water lithium hydroxide + hydrogen2Li(s) + 2H2O(l) 2LiOH(aq) + H2(g)

When added to water, lithium floats. It fizzes steadily and becomes smaller until it disappears

2008-02-04T02:53:00.000-08:00

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