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C2 - The Periodic Table - Coggle Diagram
C2 - The Periodic Table
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Group 7 - Halogens
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Have a low melting & boiling point, increases as you go down the group.
At room temp fluorine is pale yellow gas, chlorine is a green gas, bromine is red-brown liquid, iodine is grey solid.
All poor conductors of thermal energy & electricity, reactivity decreases going down the group.
All have 7 electrons in their outer shell, bond covalently with non-metal forming molecules, form ionic compounds with metals where the halide ions have a -1 charge.
Group 1 - Alkali metals
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Their compounds are usually white or colourless crystals that dissolve in water producing colourless solutions.
The metals all react with water to produce hydrogen and an alkaline solution containing the metal hydroxide.
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Soft solids at room temp - low melting & boiling points, decrease going down the group.
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Going down group 1, the reactivity of the alkali metals increases.
Electronic structures
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The atoms of metals tend to lose electrons, whereas these of non-metals tend to gain electrons.
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Explaining trends
Therefore electrons are easier for the large atoms to lose going down a group, and harder for them to gain going down a group.
In deciding when atoms gain or lose electron remember - this increased nuclear charge - due to extra protons in the nucleus - going down a group is out weighed by the 2 other factors
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You can explain trends as you go down a group in terms if the attraction between electrons in the outermost shell and the nucleus.
Reactivity in groups
When metals react, they lose electrons, so reactivity of metals increase going up the group.
When non-metals react they gain electrons, so reactivity decreases going down a group.
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Reactivity depends on the total number of electrons - going down a group, more occupied energy levels & atoms get larger. As atoms get larger electrons with the highest energy level are less attracted by the nucleus.
Group 1
reactivity increases cause the outer electron is less attracted to the nucleus as the number of energy levels increase the atoms get larger.
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Group 7
Reactivity decreases cause attraction of outer electrons to nucleus decreases as the number of energy levels increases.
More inner shells also shield the outer shell, reducing attraction for nucleus.