IB Chemistry: Metallic Bonding Metallic Bonding Describe the metallic bond as the electrostatic attraction between a lattice ofpositive ions and delocalized electron. Three signiﬁcant properties of metals are their: ◆ high melting points (as contrasted with most non-metals) ◆ high electrical conductivity ◆ high thermal conductivity Any model of bonding in metals must be able to account for these properties.The diagram below shows a representation of a simple model of bonding in asolid metal; it consists of metal ions surrounded by a “sea” of mobileelectrons. The shared “electron sea” bonds the metal ions tightly into thelattice. The electrons involved are only the valence electrons in the highestenergy level of the metal atoms. The electrons are said to be delocalised, i.e.no longer attached to one particular nucleus. This model is a simpliﬁcation butit can explain the typical metal properties mentioned above. Fig 1.1 Above is an example of a Copper ions, with a sea of electronssurrounding the positively charged atoms. The sea of electrons is largelyresponsible for coppers high electrical conductivity. Explain the electrical conductivity and malleability of metals
Electrical conductivity Electrical conductivity is simply a measure of a substances ability to conductelectricity. Metals have delocalized electrons, which are basically valence electrons thatare not bound to the atom . We call this asea of electrons. These delocalizedelectrons help the metal to conduct the electrical charge, hence accounting forthe high electrical conductivity of most metals. Malleability Let’s ﬁrst deﬁne malleability: ‘Malleability is basically the ability of a substance to deviate from its originalstructure when some stress is applied towards it’ For example, I have an iron metal container which I can bend and twist aroundat will (Don’t worry, I’m not hulk). Then the iron metal container is said to bemalleable. Some metals tend to be quite malleable. This is mainly due to the structure ofthe atom. If we revisit a previous topic where we talked about how particleswere arranged in a solid, liquid or gas, we saw that particles in a solid areclose in proximity, and can only vibrate and slide past each other withoutsigniﬁcant resistance or breaking any bond. Basically, the metal is not forcedinto any ﬁxed orientation (as they are allowed to slide across each other). Thisexplains why metals are malleable.