Yksivalenteiset

Yksivalenteiset is a Finnish term that translates to "monovalent" in English. In chemistry, a monovalent atom or radical is an element or group of atoms that has a combining or saturation capacity of one. This means it can form only one chemical bond. Examples of monovalent elements include hydrogen (H), lithium (Li), sodium (Na), and chlorine (Cl). In these cases, hydrogen and the alkali metals typically lose one electron to form a positive ion, while halogens like chlorine gain one electron to form a negative ion.

The concept of valency is fundamental to understanding chemical bonding and the formation of molecules. A monovalent atom, by definition, requires one other monovalent atom or a combination of other atoms with a total valency of one to achieve a stable electron configuration. For instance, a molecule of hydrogen chloride (HCl) is formed by the single covalent bond between a monovalent hydrogen atom and a monovalent chlorine atom. Similarly, water (H2O) is formed from one oxygen atom, which is divalent, and two hydrogen atoms.

In other contexts, "monovalent" can refer to something having a single value, characteristic, or attachment. For example, in immunology, a monovalent vaccine targets only one specific strain or type of pathogen. This contrasts with polyvalent vaccines, which are designed to protect against multiple strains or types. The term's core meaning of "one" or "single" remains consistent across different fields.