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A neutral helium atom needs 24.6 eV to eject one electron. What energy, in eV, is needed to remove both electrons from the neutral helium atom?

1. 38.2
2. 49.2
3. 51.8
4. 79.0

Correct answer: 79.0

Solution

To remove both electrons from a neutral helium atom, you need to account for the energy required to remove the first electron (24.6 eV) and the increased energy needed to remove the second electron due to the positive charge of the helium ion formed after the first electron is removed. The total energy required is 24.6 eV for the first electron plus 54.4 eV for the second, resulting in 79.0 eV.

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