grundämnen

Grundämnen, or chemical elements, are substances composed of atoms that share a common nucleus with a specific number of protons. Each element is defined by its atomic number Z, and by a characteristic electron configuration. As of today, 118 elements are known, and they cannot be broken down into simpler substances by chemical means.

Elements are arranged in the periodic table by increasing atomic number. The table reveals periodic patterns in properties such as electronegativity and reactivity. Groups (columns) tend to have similar chemistry, while periods (rows) reflect the outer electron shell.

Most elements fall into three broad classes: metals, nonmetals, and metalloids. Major families include alkali metals, alkaline earth metals, transition metals, halogens, and noble gases. The table provides a framework for predicting which elements form which kinds of compounds.

Earth contains only a fraction of the elements in the universe, which is dominated by hydrogen and helium. Heavier elements are produced in stars and stellar explosions. Elements exist as a variety of isotopes; some are stable while others are radioactive. Isotopes have many applications in medicine, dating, and tracing processes.

Historically, the concept of grundämnen emerged with the periodic law and the work of Dmitri Mendeleev, who predicted unknown elements based on patterns. The study of elements is central to chemistry, physics, biology, and materials science.