The ionization energies (kJ/mol) of hydrogen (H), nitrogen (N), sodium (Na), and oxygen (O) are 1,312, 1,402, 1,681, and 1,314, respectively. Which element combination is least likely?
NH4+

OH-

NO3-

NaO-

Question

The ionization energies (kJ/mol) of hydrogen (H), nitrogen (N), sodium (Na), and oxygen (O) are 1,312, 1,402, 1,681, and 1,314, respectively. Which element combination is least likely?
       NH4+

       OH-

       NO3-

       NaO-

anonymous · Answer

I really cannot figure this out...  Please help!

aaronq · Answer

you need to determine the oxidation state of the atoms given. The compound with the cation (meaning it lost electron(s)) with the highest ionization energy makes it the most improbable compound.

anonymous · Answer

So I'm thinking either A or D?

aaronq · Answer

the oxidation state of N in $NO_3^-$ is +5  in $NH_4^+$ it is -3