help in O1 chemistry

[lilla]

i need help in chemistry 
i don't  know those valences of elements HELP!!!! pleaseeeeeee

[toobeerajpanchoo]

u must know how much an element need eg
for Na:it has 11 electron hence electronic configuration is 2,8,1
as Na is in group 1 its valency is 1
-   Mg is in group 2 its valency is 2
-   Cu and other transition elements have variable valencies
-   Fe2+ have valency 2 and Fe 3+ have valency 3
-   Al3+ have valency 3 because it is in group 3
-   C  have electronic configuration 2,4 and it needs 2 to become fully satisfied hence valency is 2
YOU NEED JUST TO DO THE electronic configuration OF EACH ELEMENT. NUMBER IT HAS AT FINAL IN ITS electronic configuration WOULD DETERMINE ITS VALENCY AND ELEMENTS THAT ARE NOT SATISFIED FOR EXAMPLE LIKE CARBON, THE DEMANDING NUMBER WOULD GIVE ITS VALENCY

[zara]

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! =)

[MR.BooMBastiC]

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! =)

no it didnt

[zara]

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! =)

no it didnt

why?
n ya By the way it was not for you....im so sure the concerned person must have been benefited!

[slvri]

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! =)

no it didnt

why?
n ya By the way it was not for you....im so sure the concerned person must have been benefited!

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

[nid404]

check the word doc...contains valencies of a lot many elements