Elements in the same group (vertical column) of the periodic table exhibit similar chemical properties. This similarity arises because they have the same number of valence electrons, which are the electrons in the outermost shell that participate in chemical bonding. Nitrogen (N) is in Group 15. Phosphorus (P) is located directly below nitrogen in the same group. Therefore, both nitrogen and phosphorus have five valence electrons, leading to analogous chemical behaviors, such as forming similar types of ions and compounds (e.g., NH₃ and PH₃).

A. Neon (Ne) is in Group 18 (noble gases) and is chemically inert, which is very different from nitrogen's reactivity.

C. Silicon (Si) is in Group 14 and has four valence electrons, leading to different bonding patterns and chemical properties.

D. Boron (B) is in Group 13, possessing only three valence electrons, which results in chemical characteristics distinct from nitrogen.

1. Flowers, P., Theopold, K., Langley, R., & Robinson, W. R. (2019). Chemistry 2e. OpenStax. Section 3.2, "The Periodic Table," Paragraph 5. "Elements in the same column (group) of the periodic table have similar chemical properties."

2. Drennan, C. L. (2014). 5.111SC Principles of Chemical Science, Fall 2014. Massachusetts Institute of Technology: MIT OpenCourseWare. Lecture 9 Notes, "The Periodic Table," p. 4. "Elements in the same group have similar chemical properties because they have similar valence electron configurations."

3. Purdue University, Department of Chemistry. (n.d.). The Periodic Table. Retrieved from https://www.chem.purdue.edu/gchelp/atoms/period.html. Under the "Groups" section, it states, "Elements in the same group have similar chemical properties."