Question 2
Which equation represents the first ionization energy of sodium?
The right answer is the one marked above.
Na(g) → Na+(g) + e
Check the equation against the definition, piece by piece. Both sides are marked (g), so everything is gaseous. One electron leaves. And the ion left behind carries a single positive charge. Na+(g) + e → Na(g) is this reaction run backwards, which is a different quantity altogether.