The atomic number of an element represents the number of protons in its nucleus. It is a defining characteristic of an element and determines its chemical properties. For instance, the atomic number of the element gold is 79, meaning each gold atom contains 79 protons.
Knowing the atomic number of elements is crucial for various reasons. It helps scientists predict the chemical behavior of elements, enabling them to develop new materials and technologies. Historically, the discovery of atomic numbers by Henry Moseley in 1913 revolutionized chemistry by organizing elements into the periodic table based on their atomic numbers.
