一條Chemistry Eassy.

The essay should mention the following things:
1) the number of outermost electrons of the elements in the same group are the same. They therefore exhibit similar reaction pattern.
2) The only different is the number of electron cells. When going down the group, there will be more electron cells and the metallic characters of the element will increase.
3) The group I and Group II metals tend to lose the outermost electron to obtain the octet structure. Due to the same number of outermost electrons, they will form the ions with teh same valency.
4) When going down the group, due to the increase of metallic character or the ease to lose electron, the reactivity will be faster.

in order to save time I give point form only
Gp 1
(a)They are soft and easily to be cut by knife due to weak metallic bond.Since only 1 e- is involved in forming metallic bonds But when moving along the group, they become sofer due to the increase in quatum shell.And thus weak attraction force generated between outermost shell e- and nucleus.
(2)they are packed in BCC(body center cubic)
(3)they are shiny but will be oxidized by oxygen in air easily
(4)they react with water to give hydroxide M + H2O -----> MOH + H2
(5)they react with Chlorine gas M + Cl2 ------>2MCl
(6)they react with oxygen to give oxide, peroxide and superoxide
Metal------oxide-------peroxide------superoxide
Li--------------Y-------------N------------------N
Na-------------Y------------Y*------------------N
K -------------N--------------Y-----------------Y*
Rb-------------N--------------Y-----------------Y*
Cs-------------N--------------Y-----------------Y*
Key:
N = No
Y = Yes,minor product
Y*= Yes major product
(7)they react with acid to give salt and hydrogen gas
(8)they don't form any complex due to low charge density , large in atom size and unable to use the low lying vacant 3d orbital with the exception of Li due to its small size and higher charge density.
(9)they have very low I.E when moving down the group due to the increase in quatum shell.And thus weak attraction force generated between outermost shell e- and nucleus.
(10)They are very electropositive and are the great reducing agents.


For group 2
(a)They are harder and less easily to be cut by knife due to stronger metallic bond.Since only 2 e- is involved in forming metallic bonds But when moving along the group, they become sofer due to the increase in quatum shell.And thus weak attraction force generated between outermost shell e- and nucleus.
(2)they are packed in HCP and FCC(body center cubic) and hence harder.
(3)they are not as shine as group 1 metal but will be oxidized by oxygen in air .
(4)they react with water to give hydroxide M + H2O -----> MOH + H2 with the expection of Mg and Fe. Steam must be used instead of water.
(5)they react with Chlorine gas M + Cl2 ------>MCl2
(6)they react with oxygen to give oxide only. They hardly form peroxide and superoxide.
(7)they react with acid to give salt and hydrogen gas
(8)they don't form any complex due to low charge density , large in atom size and unable to use the low lying vacant 3d orbital with the exception of Be due to its small size and high charge density.
(9)they have low I.E when moving down the group due to the increase in quatum shell.And thus weak attraction force generated between outermost shell e- and nucleus.
(10)They are very electropositive and are the great reducing agents.

There are some more points but I can't remember. Sorry.

2007-02-02 19:48:33 補充：
metal oxides group1 can react with water to give M2O(oxide)(s) H2O(l) ------- 2MOH(aq)M2O2(peroxide)(s) H2O(l) ------- MOH(aq) H2O2(aq)2MO2(superoxide)(s) H2O(l) ------- MOH(aq) H2O2(aq) O2For group 2 metal oxide give MO(s) H2O(l) ------- M(OH)2