a. Among `Cu^(o+)`,`Cu^(2+)` and `Cu` which is the largest in size and why?
b. Which element in periodic table has the highest `IE` (ionisation energy)?
c. Which element, `Mg` or `Al`, is more metallic and why?

Explanation

a. `Cu` is largest due to less effective nuclear charge. It has `29` electrons , `29` protons, `Cu^(+)` has `28` electrons and `29`protons, `Cu^(2+)` has `27` electrons and `29` protons .
b. He has the highest ionisation energy.
c. `Mg` is more metallic due to lower ionisation energy.