Question

DUPLICATE Write a chemical equation representing the second ionization energy for lithium.

Answer 1

Ionization energy is the tendency of an atom to release an electron.
It decreases down the group and increases across the period in the periodic table:
First ionization energy means removal of electron form Li:
Li --> Li+ + 1 e- 
The 2nd ionization energy is removing a 2nd electron from that resulting cation: 
Li+ --> Li2+ + 1e-