When two elements of comparable electron affinities and high ionization energies are allowed to react, then the bond formed is?
Answers
Explanation:
Third in importance for bond formation after size and ionization energy is the energy change accompanying the attachment of electrons to a neutral atom. This energy is expressed as the electron affinity, which is the energy released when an electron is attached to an atom of the element. In many cases, the electron affinity is positive, signifying that energy is indeed released when an electron attaches to an atom. Such is the case when the incoming electron enters a vacancy in the valence shell of the atom. Although it is repelled by the electrons already present, it is sufficiently close to the nucleus for there to be a net attraction. Hence, the energy of the electron is lower when it is a part of the atom than when it is not. However, if the incoming electron has to start a new shell because the orbitals of the neutral atom are full, then it remains so far from the nucleus and so strongly repelled by the electrons already present that there is a net repulsion, and energy must be supplied to attach the electron to form an anion. In such cases, the electron affinity is negative.