How is the atomic number defined?

The atomic number is defined as the number of protons in the nucleus of an atom. This fundamental property uniquely identifies each element and determines its position in the periodic table. For instance, hydrogen has an atomic number of 1, which means it has one proton, while carbon has an atomic number of 6, indicating it has six protons.

The atomic number plays a crucial role in defining the chemical behavior of an element, as the number of protons also corresponds to the number of electrons in a neutral atom. Therefore, the atomic number not only identifies the element but also influences its reactivity and bonding with other elements. Understanding the atomic number is vital in studies of chemistry and biology, as it underpins the foundational concepts of elements and their interactions.