Question

When the screening effect increases, ionisation
energy​

Answer 1

The more electrons shielding the outer electron shell from the nucleus, the less energy required to expel an electron from said atom. The higher the shielding effect the lower the ionization energy. It is because of the shielding effect that the ionization energy decreases from top to bottom within a group.

Answer 2

Explanation:

Ionization energy (IE) is the energy required to remove the highest-energy electron from a neutral atom. In general, ionization energy increases across a period and decreases down a group. ... The increased distance weakens the nuclear attraction to the outer-most electron, and is easier to remove (requires less energy).

How to Calculate the Ionization Energy of Atoms

Determine what atom you want to use for calculating the ionization energy. ...

Decide how many electrons the atom contains. ...

Calculate the ionization energy, in units of electron volts, for a one-electron atom by squaring Z and then multiplying that result by 13.6.