Group I (Alkali metals)
Group I elements are metals having metallic properties. However they are soft and low densed elements.
These metals react with water rapidly. As the reactivity of the metals increases down the group, their reactivity with water is increased down the group. More vigorous reaction can be observed between cold water and potassium . Reaction of Cesium with water is even explosive. Reaction produces hydroxide and hydrogen gas.
Group VII (the halogens)
halogens are non metals and all the elements exists as diatomic molecules. e.g Cl2
Their physical nature changes down the group. Fluorine and Cl are gases, Br is a liquid and Iodine is a solid. Fluorine is a colourless gas, Chlorine is a gas with pale yellow color, Bromine is brown color and iodine has a more dark color violet.
According to their reacivity decreases down the group, they show a characteristic displacement reaction. That is the more reactive halogen is able to displace the less reactive halogen from its compound.
e.g : HCl
If Fluorine is added to HCl the followin reaction willl occur.
F2 + 2HCl ---> 2HF +Cl2
If Iodine was added instead of Chlorine, No reaction will occur as iodine is less reactive than chlorine.
Grop 0 ( the noble gases)
All the nobel gases has a fully filled outermost shell. Elements show reactivity to achieve fully filled outermost shells as it is the most stable state for elements. Nobel gases have fully filled outer most shell. Therefore they are already stable and are not reactive.
The lack of reactivity of the nobel gases are used where an inert atmosphere is necessary.
12:19 AM
alkali metals
chemistry
displacement reactions
GCSE
Group 0
Group I
group trends
group VII
halogens
nobel gases
reactivity
Uses
