Which equation represents the first ionization of calcium?

The equation represents the first ionization of calcium is $\begin{array}{r}\mathrm{Ca}\left(g\right)\to {\mathrm{Ca}}^{+}\left(g\right)+e^{-}\end{array}$. 

Initial ionisation The energy needed to take the first electron out of a neutral atom is called the removal energy. It has the same numerical value as the electron's orbital energy but the opposite sign.