Question

which atom requires higher ionization energy to remove its valence electron? why?
when we move - down a group in the periodic table, (more, less) energy levels are added, and so valence electrons would become
and
away from the positive nucleus.
this causes the attraction between valence electrons and the nucleus to (increase, decrease), something known as the “shielding effect”.
the (more, less) attraction between the electrons and the nucleus, the
they are to remove - decreasing ionization energy.
which atom requires higher ionization energy to remove its valence electron? why?
bohr model of magnesium atom
when we move down a group in the periodic table,
energy levels are added, and so valence electrons would become
and
away from the positive nucleus.
this causes the attraction between valence electrons and the nucleus to
, something known as the “shielding effect”.
the
attraction between the electrons and the nucleus, the
they are to remove - decreasing ionization energy.

Explanation:

Step1: Analyze electron - nucleus attraction

As we move down a group in the periodic table, more energy levels are added. Valence electrons become farther and more shielded from the positive nucleus. This causes the attraction between valence electrons and the nucleus to decrease due to the shielding effect. The less the attraction between electrons and the nucleus, the easier they are to remove, resulting in lower ionization energy.

Step2: Compare sodium and potassium

Sodium ($Na$) has atomic number 11 and potassium ($K$) has atomic number 19. Potassium is below sodium in Group 1 of the periodic table. Potassium has more energy levels, so its valence electron is farther from the nucleus and more shielded. Sodium has a higher ionization energy because its valence electron is closer to the nucleus and experiences a stronger attraction.

Step3: Compare sodium and magnesium

Sodium has 1 valence electron and magnesium ($Mg$) has 2 valence electrons. Magnesium is in Group 2 and sodium is in Group 1. Magnesium has a higher effective nuclear charge (the net positive charge experienced by an electron) because it has more protons in the nucleus while the valence electrons are in the same energy level as those of sodium. So, magnesium has a higher ionization energy as it is more difficult to remove its valence electron due to the stronger attraction from the nucleus.

Answer:

Magnesium has a higher ionization energy than sodium, and sodium has a higher ionization energy than potassium. Magnesium's higher ionization energy compared to sodium is due to its greater effective nuclear charge as it has more protons in the nucleus for the same outer - energy level. Sodium has a higher ionization energy than potassium because potassium's valence electron is in a higher energy level, farther from the nucleus and more shielded.