Electron Affinity

What is electron affinity?

The amount of energy released when an electron is added to an atom.

What is the trend for electron affinity across a period?

Electron affinity increases from left to right across a period because the increasing attraction between the nucleus and electrons creates a stronger affinity for electrons.

Why does electron affinity increase up a group?

Moving up a group reduces the number of electron shells, which decreases shielding and brings the nucleus closer to the valence electrons, increasing nuclear attraction and electron affinity.

Why do Group 2 elements have low electron affinity?

have filled s-orbitals, making it energetically unfavorable to add another electron.

Why do Group 15 elements have lower electron affinity than Group 14 elements in the same period?

have half-filled p-orbitals, which are relatively stable, making it less favorable to add an electron compared to Group 14 elements.

Why do noble gases have negligible electron affinity?

have completely filled electron shells, making them highly stable and uninterested in gaining additional electrons.

What is the general trend for electron affinity on the periodic table?

Electron affinity increases from left to right across a period and increases going up a group.