Oganesson - Og (Atomic number 118) These elements are organized in the periodic table based on their atomic numbers, which increase sequentially from 1 (Hydrogen) to 118 (Oganesson).

Atomic number 25, atomic weight 54.9380. Phosphorus (P): Phosphorus is a poisonous, nonmetallic element that helps protect metal surfaces from corrosion. Atomic number 15, atomic weight 30.9738.