Question

Why is the second ionization energy higher than first?

Answer 1

Ionization energy:

• The amount of energy required to eject the last electron from the outermost shell of an atom in its isolated gaseous state is called ionization energy.
• The energy required to eject the first electron is called first ionization energy.
• Similarly, the energy required to eject the second electron is called second ionization energy.

Reason:

• Now when the first electron is ejected out lesser energy is required because the ejection is done from a neutral atom.
• But when it comes to second ionization energy, now ejection is done from a positive ion, where the effective nuclear charge is now increased (number of protons is now more than that of electrons), and electrons are now more attracted towards the nucleus.
• Hence it becomes difficult to eject the second electron, which implies that the second ionization energy is relatively higher than the first.