Which of the following surfaces does a true monolayer always form on?
A. silicon
B. gold
C. both
D. neither
To determine which of the surfaces, silicon or gold, always form a true monolayer, we need to understand the concept of a monolayer and the behavior of these materials.
A monolayer refers to a single layer of molecules or atoms that are chemically or physically adsorbed onto a surface. This layer is typically formed when molecules or atoms from a gas or liquid phase come into contact with a solid surface.
Now, let's consider the behavior of silicon and gold:
A. Silicon: Silicon is a semiconductor and has a particular surface structure. However, whether a true monolayer can form on silicon depends on the specific conditions, such as the type of molecules or atoms in contact with the surface. In some cases, silicon can form a monolayer, while in others, it may form multiple layers or undergo a different type of adsorption.
B. Gold: Gold is a metal and has a surface structure that is more favorable for the formation of monolayers. Gold surfaces have been extensively studied for their ability to form self-assembled monolayers (SAMs) due to their affinity for various organic molecules. SAMs are well-defined monolayers formed by the spontaneous adsorption of molecules onto a solid gold surface.
Therefore, option B, gold, is more likely to always form a true monolayer compared to silicon. While silicon can form a monolayer in certain conditions, gold's surface properties make it more suitable for the formation of consistent monolayers.