Question

explain in your own words why ionization energy decreases as atomic number increases from top to bottom of the periodic table.

Explanation:

As atomic number increases from top to bottom in a group of the periodic table, the number of electron shells increases. This means the outermost electrons are further from the nucleus. The increased distance reduces the attractive force from the nucleus (due to shielding by inner electron shells). With less attraction, less energy is needed to remove the outermost electron, so ionization energy decreases.

Answer:

Ionization energy decreases from top to bottom in the periodic table because as atomic number increases, electron shells are added, moving outer electrons farther from the nucleus. Inner shells shield outer electrons from the nucleus's pull, weakening the attraction. Less energy is then required to remove the outer electron.