The first element in the periodic table is hydrogen.
Hydrogen is the simplest and most abundant element in the universe. It has one proton and one electron, which gives it an atomic number of 1. This means that hydrogen is the building block of all other elements, being the lightest element and the first in the sequence of the periodic table. Due to its simplicity, hydrogen plays a key role in various chemical reactions, including those that power stars and produce energy in our own bodies through cellular respiration. Understanding hydrogen is essential for studying chemistry and atomic science.