if it skips out of our mind then you can paste the valency table just above our study table so that you can see it every time and i am sure after some days it will be in your finger tips .i have also remembered it in this way.
 i hope that this will help u.....^_^
1 5 1
sry for that
it's not a big deal.
okay then see you in another question. bbye.
it's okay. I already said.
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It is not so difficult.  We know many compounds already with their formulas.

1) we know the valency of  some elements already  like hydrogen, fluorine, chlorine, oxygen, Sodium, potassium, bromine, carbon, nitrogen  ....

2) from known valencies we can get the valency of the unknown ones, as the neutral elements, molecules and compounds have 0 total valency..

3) Ions have total valency = charge on them.

4) If you remember the position of the element in the periodic table or, if you know the group to which this element belongs, then you know the valency easily.

5)  If you know the electronic configuration of the elements, (if this subject is already covered) then it is easier.

6) There is no difficulty with simple elements.  But with Copper, Iron Fe, Phosphorus, Sulphur, Nitrogen - some compounds exist with them in multiple  oxidation level and valencies.  There comes some difficulty.

     Remember  like     SO4 has 2 minus.    NO3  has one -.    This way too you can calculate the valency values.
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wow masterji
very nice:))
thanks... nice of you
oh thank you so much sir its very halpful to me than you so much