The element with the most similar properties to nitrogen is phosphorus. Nitrogen and phosphorus are both nonmetallic elements that belong to Group 15 of the periodic table. They have similar atomic structures and chemical properties. Nitrogen has an atomic number of 7, while phosphorus has an atomic number of 15. Both elements have three valence electrons, which means they can form three covalent bonds with other atoms. Nitrogen and phosphorus also have similar electronegativities, which means they have a similar tendency to attract electrons in a chemical bond. This similarity in electronegativity results in similar chemical bonding properties for nitrogen and phosphorus. For example, both elements form covalent bonds with hydrogen to form ammonia (NH3) and phosphine (PH3), respectively.