Final answer:
Nitrogen has a higher electron affinity than phosphorus due to its greater number of protons in its nucleus, which leads to stronger coulombic attraction.
Step-by-step explanation:
In terms of coulombic attraction, nitrogen has a higher electron affinity than phosphorus due to its greater number of protons in its nucleus. The coulombic attraction between the positively charged protons in the nitrogen nucleus and the negatively charged electrons is stronger compared to phosphorus, which has fewer protons.
This stronger attraction leads to a higher tendency for nitrogen to attract electrons and thus a higher electron affinity.