The electron configuration 1S\(^2\) 2S\(^2\) 2P\(_x\)\(^2\) contravenes the 

The oxidation number of Chromium in Na\(_2\)Cr\(_2\)O\(_7\) is 

The most important ore of aluminium is 

Bases normally 

The product formed when concentrated sodium chloride solution is electrolysed using carbon electrodes is