Qualification > Sciences
help in O1 chemistry
slvri:
--- Quote from: Z.J. on August 30, 2009, 06:34:28 pm ---
--- Quote from: 007-JaMeS BooM on August 30, 2009, 05:41:54 pm ---
--- Quote from: Z.J. on August 30, 2009, 05:37:40 pm ---the group number is the valency number for all elements until grp 4
for grp 5 6 and 7 you subtract it from 8 [example: for an element in grp 5 the valency will be 8-5=3]
for transition elements the valencies vary.
and the period number determines the number of orbits/shells of that element.
hope it helped! =)
--- End quote ---
no it didnt :P ;D
--- End quote ---
why?
n ya By the way it was not for you....im so sure the concerned person must have been benefited! :)
--- End quote ---
yea...that rule works in most cases ;)
Ghost Of Highbury:
Group : 1 2 3 4 5 6 7 0
Valency:1 2 3 4 3 2 1 0
note : transition elements have different valencies( elements with variable valencies)
for e.g - Cu+ ; Cu2+
Fe2+ ; Fe3+
Pb2+ ; Pb4+
sulphur has a valency of 4 and 6
phosphorous has a valency of 3 and 5
nid404:
Ok
First ill make the difference between valence electrons and valency clear
Valence electrons are the number of electrons in the outermost shell of an atom
Valency of an atom is the number of electrons it needs to lose or gain in order to attain the nearest noble gas atomic structure
So, as aforementioned
The valency of atoms is its group number till group no 4
Following that, the valency is 8-group number(or valence electrons)
Transition elements, as mentioned earlier can have varying valencies....you must know the common ones
nid404:
http://www.gcsescience.com/periodic-table.htm
visit this site
click on the links and enjoy learning
Ghost Of Highbury:
find a pdf attached...
few of the slide contains notes on valency
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