To solve this problem, we need to understand the concept of first ionization enthalpy.$\\$First ionization enthalpy is the energy required to remove the outermost electron from a neutral atom in the gaseous state.$\\$The general trend in the periodic table is that ionization enthalpy increases across a period from left to right$\\$due to increasing nuclear charge and decreases down a group due to increasing atomic size.$\\$Let's analyze the given elements: Li, Be, B, C, N. All these elements belong to the second period of the periodic table.$\\$• Li (Lithium) is in Group 1.$\\$