Question

The periodic property which relates the amount of energy required to remove the electron from the outermost shell of an isolated gaseous atom ____________.

Answer 1

Ionization energy

The minimum amount of energy required to remove the electron from the outermost shell of an isolated gaseous atom is called ionization energy.

Across the period:

1. Atomic size decreases due to the increase in nuclear charge.
2. This increases electronegativity and causes difficulty in removing the valence electrons.
3. Thus, Ionization energy increases.

Down the group:

• Atomic size increases with the addition of new shells.
• This decreases the nuclear charge and increases electro-positivity.
• Thus, Ionization energy decreases.

FINAL ANSWER: The periodic property which relates to the amount of energy required to remove the electron from the outermost shell of an isolated gaseous atom is ionization energy.