A chemical element is a pure substance that consists of atoms with the same number of protons in their atomic nuclei. Each element is represented by a unique symbol, typically consisting of one or two letters. Elements are the fundamental building blocks of matter and cannot be broken down into simpler substances through chemical reactions.

The periodic table of elements is a tabular arrangement of all known elements, organized based on their atomic number, electron configuration, and recurring chemical properties. There are currently 118 confirmed elements, with the first 94 occurring naturally on Earth and the rest being synthetic, created through various nuclear reactions.