Question

Compare the first ionization energy of helium with its second ionization energy, remembering that both electrons come from the 1s orbital. Explain the difference without using actual numbers from the text.

Short answer

For helium, the first ionization energy is always lesser than the second ionization energy.

Step-by-step solution

Analyze the first ionization energy of helium.

In the case of the first ionization energy,

The electron is removed and the remains the second electron. The ionization energy is massive since the nucleus is close to the atom.

Analyze the second ionization energy of helium.

After one electron is removed, the second electron which is close to the nucleus requires more ionization energy. The force of attraction is more since all the force of the nucleus is centred on this atom. Hence, the second ionization energy is more than the first ionization energy.