Answer: 1+
Justification:
The ionization energy is the amount of energy needed to loose electrons and becomes ions.
The first ionization energy is the energy needed to liberate one one electron and form the ion with oxidation state 1+.
The second ionization energy is the energy to release a second electron and form the ion with oxidation state 2+.
The third ionization energy is the energy to leave a third electron free and form the ion with oxidation state 3+.
The relatively low first ionization energy of element 2, shows it it will lose an electron easily to form the ion with oxidations state 1+.
The second and third ionization energies are very high meaning that the ions with oxidation staes 2+ and 3+ will not be formed.
Therefore, the answer is that the expected oxidation state for the most common ion of element 2 is 1+.
