Definition - What does Valence Effect mean?
Valence Effect is a phenomenon in which the loss of stability of emulsions and colloidal suspensions increases as the valence number of an ion increases. Valence number is defined as a whole number (positive or negative) representing the power of one element to combine with another. The valence number can be easily given up or accepted to react with or bond to another atom or group of atoms to form a molecule.
Petropedia explains Valence Effect
Since oil and gas hydrocarbons form an emulsified and colloidal solutions, stability is an important factor and thus, the valence effect needs to be minimum, i.e., the valence number of hydrocarbon ions needs to be low.
When considering the electronic configuration of an atom, electrons can be divided into two categories, according to their positions in an atom: valence and core electrons. Valence electrons are those that occupy the outermost shell or highest energy level of an atom, while core electrons are those that occupy the innermost shell or lowest energy level. Generally, valence electrons can participate in the formation of chemical bonding, but core electrons cannot. The number of valence electrons is critical to the chemical property of an atom.
The chemical reactivity of an atom is mainly determined by valence electrons. Atoms which have a complete shell of valence electrons tend to be chemically inert while atoms with one or two valence electrons are highly reactive. Valence electrons are also responsible for the electrical conductivity of an element, and as a result, an element may be classified as a metal, nonmetal or semiconductor (metalloid).