Concept:Electron affinity is the energy change that occurs when an isolated gaseous atom gains one electron.
Explanation:Consider a neutral gaseous atom, represented as
X(g).
When this atom accepts an electron, it forms a negative ion:
X(g)+e−→X−(g)The energy change involved in this process is known as the electron affinity of the atom.
This definition is specifically for atoms in the gaseous state.
It is different from ionization energy, which is the energy required to remove an electron from a gaseous atom.
It is also different from electronegativity, which refers to the attraction of an atom for shared electrons in a chemical bond.
Atomization, on the other hand, is the energy change when one mole of a substance is converted into free gaseous atoms.
Therefore, the correct term for the energy change on adding an electron to a gaseous atom is electron affinity.
Answer:B. electron affinity