Question

how calculate valency

Answer 1

calculating valency is very easy when you are very much confident with the atomic number of the elements. just study the order of the elements,it will have the atomic number likely.
for example see carbon, it is the 6th element in the order and has the atomic number also six.similarly just remember the order.
when u know the atomic number just try the electron distribution with the shells and the no.of electrons in the last shell will do the trick.
if it is 1,2,3 or even 4,u should see whether adding more element to the shell to make it stable is better or to remove the little no.of electrons is better.for example take lithium.it is 3rd and has valence electron 1.it is better to take away 1 electron rather than adding 7 more to make it stable. so 1 is the valency of lithium.
hope it helps !!!
thanks