It's a general trend that basicity of oxides decreases down the group.
But recently I came across a statement "the basicity of second group oxide decreases down the group and decrease in basic nature of oxide from Be to Ba is due to decrease in polarizing power with increase in ionic size"
I'm not able to understand the relationship between ionic nature and basicity.
Also I feel that more the ionic nature, more the basicity, (as oxygen easily dissociates )
This is question is related to this , but generalised explaination is given, I'm looking for specific explaination to this this particular case