Consider the following statements regarding the periodic trends of elements: A. The first ionization enthalpy of oxygen is lower than that of nitrogen. B. The negative electron gain enthalpy of fluorine is higher in magnitude than that of chlorine. C. Among the isoelectronic species N³⁻ , O²⁻ , F⁻ , Na⁺ , and Mg²⁺ , the ionic radius of Mg²⁺ is the smallest. D. Electronegativity generally decreases across a period fro

Step-by-step solution

Statement A: Nitrogen has a stable half-filled 2p³ electronic configuration, making its first ionization enthalpy higher than that of oxygen ( 2p⁴ ). Thus, statement A is correct. Statement B: Due to the small size of the fluorine atom, there are strong interelectronic repulsions in its 2p subshell. Therefore, the negative electron gain enthalpy of chlorine is higher in magnitude than that of fluorine. Thus, statement B is incorrect. Statement C: For isoelectronic species, the ionic radius decreases as the nuclear