valancies!!?

Question

Does any one have any tips how to remember the valencies pls?

Answer 1

Its easy!

The valency of an atom in group 1 is +1. (This is because it has one electron on its outer shell, and it needs to give up this electron to become more stable by loosing it and going back to the last fully filled subshell)

The valency of an atom in group 2 is +2 (for the same reason!)

As you go to the right hand side of the periodic table, the signs change. For example, the valency of group 8 atoms is 0. This is because group 8 atoms have the maximum number of electrons on their outer shell so are not reactive, ie have no charge!

But group 7 atoms (halogens) have a valency of -1. (Ie they need one electron to become stable)

Likewise group 6 atoms have a valency of +2 because they need 2 electrons to become stable!

Thats how you remember the valancies!

P.S. There are exceptions to this in the transition elements as transition elements have variable valencies!

Hope Ive helped!

Answer 2

As mentioned in the previous answer,the transitions elements have variable valencies.

Leaving those trasition elements, number the groups,
gr1-1,gr2-2,gr3-3,gr4-4,gr5-3,gr6-2,gr7-1, andgr8- 0. Now you have the valencies of elements in group1 to group8.