electron affinity vs ionization energy

[annie_finneran_1K]

I am a bit confused on the difference between these 2 concepts and the patterns in the table for each. Question 2.67 talks about which element will have higher electron affinity and it seems to follow the same trend as ionization energy. is this a trend that we can follow throughout the table or are the concepts and patterns separate?

[Solene Poulhazan]

I believe that we can just follow the same trends for both of these concepts. For electron affinity and ionization energy, it increases across a period and decreases down a group.

[Steven Luong 1E]

Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. In other words, the neutral atom's likelihood of gaining an electron. Ionization energy is defined as the energy needed to remove one electron. Ionization energies are always concerned with the formation of positive ions. Electron affinities are the negative ion equivalent. Electron affinity increases upward for the groups and from left to right across periods of a periodic table because the electrons added to energy levels become closer to the nucleus, thus a stronger attraction between the nucleus and its electrons. Remember that greater the distance, the less of an attraction; thus, less energy is released when an electron is added to the outside orbital. In addition, the more valence electrons an element has, the more likely it is to gain electrons to form a stable octet. The less valence electrons an atom has, the least likely it will gain electrons. For ionization energy, the increase in radius makes it easier to pull out a valence electron due to decreased attraction by the nucleus, so ionization energy will exhibit the same trends as electron affinity.