Question

which equation represents the second ionization energy for an atom?$x^+ \
ightarrow x^{2+} + e^-

$$x \ ightarrow x^{2+} + 2e^-$$

2x^{2+} + e^- \
ightarrow 2x$$x^{2+} + 2e^- \
ightarrow x$

Explanation:

Ionization energy is the energy required to remove an electron from a gaseous atom/ion. The second ionization energy specifically refers to removing one electron from a singly charged positive ion (formed after the first ionization) to create a doubly charged positive ion, releasing the electron.

• The first option shows a singly charged ion $X^+$ losing one electron to form $X^{2+}$, which matches the definition of second ionization energy.
• The second option shows a neutral atom losing two electrons, which is the sum of first and second ionization energies, not the second alone.
• The third and fourth options show electron gain (reduction), which is the opposite of ionization (oxidation/electron loss).

Answer:

$X^+
ightarrow X^{2+} + e^-$