Question

which equation represents the first ionization energy for an atom?
$x^++e^- \
ightarrow x^-$
$x+e^- \
ightarrow x^-$
$x \
ightarrow x^++e^-$
$x^++e^- \
ightarrow x$

Explanation:

First ionization energy is defined as the energy required to remove one electron from a neutral gaseous atom, producing a positively charged ion and a free electron. We match this definition to the correct reaction.

Answer:

X→X⁺+e⁻