Final answer:
EA refers to the change in energy when an electron is added to a neutral atom. Across the periodic table, EA generally increases, but there is no definitive trend when going down the table. These trends are important for predicting reaction rates.
Step-by-step explanation:
The Electron Affinity (EA) in chemistry refers to the energy change that occurs when an electron is added to a neutral atom in the gaseous state to form a negative ion. This is usually expressed in kilojoules per mole (kJ/mol). It's important to note that EA demonstrates some periodic trends.
As you go across the periodic table (as→PT, EA ↑), the magnitude of the electron affinity generally increases.
Although there is not a definitive trend as you go down the periodic table because EA can either increase or decrease, the general trend across the table should be evident, with variations such as the larger positive EA values observed in the second column.
It is also relevant to consider that for similar reactions under comparable conditions, the reaction with the smallest EA will typically occur most rapidly. This is a key concept when predicting and comparing reaction rates.