Ionization energies generally increase with increasing atomic number across the second row of th

step 1 As we go across the periodic table, ionization energy increases, and electron affinities decreas

Ionization energies generally increase with increasing...

Key Concepts

Effective Nuclear Charge

Effective nuclear charge is the net positive charge experienced by an electron in an atom after taking into account the shielding provided by inner electrons. As atomic number increases across a period, the effective nuclear charge felt by the outer electrons also increases, enhancing their binding energy and thus increasing the ionization energy, even though this same effect doesn't uniformly enhance electron affinity due to additional repulsion factors.

Electron-Electron Repulsion

Electron-electron repulsion becomes significant in compact orbitals as atoms get smaller across a period. When an electron is added to such an atom, the presence of other electrons in a limited spatial region causes repulsion, which can counteract the attractive force of the nucleus. This is why, despite the stronger nuclear pull that might be expected to increase electron affinity, the energy gained upon electron addition is sometimes less than anticipated.

Ionization Energy

Ionization energy refers to the amount of energy required to remove an electron from an atom. This energy increases as the effective nuclear charge increases across a period, meaning electrons are held more tightly due to a greater net positive charge in the nucleus. The decrease in atomic radius as you move across the row also contributes, as electrons are closer to the nucleus and more strongly attracted, making them harder to remove.

Electron Affinity

Electron affinity is the energy change that occurs when an electron is added to a neutral atom. While one might expect that the increased nuclear charge would lead to more energy being released upon adding an electron, electron affinities can decrease because of increased electron-electron repulsion in a small, crowded space. The added electron may experience significant repulsion from electrons already present, which can reduce the overall energy gain.

Transcript

Please give Ace some feedback