Wave–particle duality operation of chemical reactions. Electricity, first thought to be a fluid, was now understood to consist of particles called electrons. This was first demonstrated by J. J. Thomson in 1897 when, using a cathode ray tube, he found that an electrical charge would travel across a vacuum. Since the vacuum offered no medium for an electric fluid to travel, this discovery could only be explained via a particle carrying a negative charge and moving through the vacuum. This electron flew in the face of classical electrodynamics, which had successfully treated electricity as a fluid for many years (leading to the
Point of zero charge Point of zero charge The point of zero charge (pzc), in physical chemistry, is a concept relating to the phenomenon of adsorption, and it describes the condition when the electrical charge density on a surface is zero. It is usually determined in relation to an electrolyte's pH, and the pzc value is assigned to a given substrate or colloidal particle. For example, the pzc of solid FeOOH is 9. In other words, pzc is (usually) the pH value at which a solid submerged in an electrolyte exhibits zero net electrical charge on the surface. A related concept in electrochemistry is