Devender

In the last post , I discussed the difference in bonding between metals and ceramics, and how that is manifested in different properties exhibited by metals and ceramics. Now, let us try to understand why metals actually conduct electricity. The reason again ties down to bonding in metals. Like, I explained here , metals typically exhibit metallic bonding in which all the valence electrons are shared by all the atoms. There is a delocalization of electrons, unlike in covalent and ionic bonds which confine electrons only to neighboring atoms. Now, when an external electric field is applied to metals, these delocalized electrons are easy to move and thus conduct. This simple explanation is basis for Drude Model where Drude actually derives simple quantitative formula for conductivity. This explanation and thus theory is very elementary and is not be able to give correct quantitative numbers for many other properties (heat capacity and seebeck coefficient) of metals. A more detailed th

Recently, I have decided to change the blog to more science oriented. I have started a podcast ( link ) where I have decided to share my understanding of various topics in science. I will try to post 3-4 posts a week on topics related to science. So, for this post let's discuss why certain solids are metals and some ceramics. Solids, in general, can be distinguished as metals, ceramics and polymer. I am keeping the focus on difference between metals and ceramics and not going to discuss polymers in this post. If you checked my last post, matter exist in form of solid due "bonds" which keep atoms together in solid. I discussed three forms of bonds- metallic, covalent and ionic. Metals typically have metallic bonding, which is a delocalized bond where all the valence electrons are shared by each and every atoms. In contrast, covalent and ionic bonds are localized between neighborliness atoms. Atoms in ceramics typically are bound by covalent and ionic bonds. This is the

Why do matter exist as solids? Common forms of matter are solid, liquid and gas. Reason behind existence of matter as any form is governed by interactions between atoms. Electrons surrounding atoms' dictate this interaction. This interaction is what we call as a bond. So, why do atoms interact? Reason for any interaction has to do with decreasing overall energy of the system. There are three possible ways for electrons to interact with electrons of neighboring atoms: - Atom can share electrons with neighboring atom: known as covalent bond - One atom gives away its electron to neighboring atom: known as ionic bond - Atoms share electron with all the whole system, not just surrounding atom: known as metallic bond Like I said before, driving force for atoms interaction is to decrease their energy. Now, this interaction which is termed as bonds is what keep atoms together and forms solid. Solid will fell apart and form gas if there are no bonds. Now, these bonds determine how