ionization energy

Question

The first ionization energy of hydrogen atom is 13.6 eV. What is the ionization energy of He⁺ ion?

RankGuru · Accepted Answer

For hydrogen-like species (single-electron systems), the ionization energy is:
$IE = (13.6 	ext{ eV}) 	imes Z^2$
1. **Hydrogen ($H$)**: $Z = 1 \implies IE = 13.6 	ext{ eV}$.
2. **Helium Ion ($He^+$)**: $Z = 2$.
$IE_{He^+} = 13.6 	imes 2^2 = 13.6 	imes 4 = 54.4 	ext{ eV}$
- The higher charge of the helium nucleus ($+2$) attracts the single electron much more strongly than the hydrogen nucleus ($+1$), requiring 4 times more energy to remove it.

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ionization energy

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