University:
College
Course:
College Chemistry
Academic year:

2023
Views:

9

Pages:

2
Author:

anon

IB Chemistry: Metallic Bonding Metallic Bonding Describe the metallic bond as the electrostatic attraction between a lattice of positive 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 a solid metal; it consists of metal ions surrounded by a “sea” of mobile electrons. The shared “electron sea” bonds the metal ions tightly into the lattice. The electrons involved are only the valence electrons in the highest energy 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 but it can explain the typical metal properties mentioned above. Fig 1.1 Above is an example of a Copper ions, with a sea of electrons surrounding the positively charged atoms. The sea of electrons is largely responsible 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 conduct electricity. Metals have delocalized electrons, which are basically valence electrons that are not bound to the atom . We call this asea of electrons. These delocalized electrons help the metal to conduct the electrical charge, hence accounting for the high electrical conductivity of most metals. Malleability Let’s first define malleability: ‘Malleability is basically the ability of a substance to deviate from its original structure when some stress is applied towards it’ For example, I have an iron metal container which I can bend and twist around at will (Don’t worry, I’m not hulk). Then the iron metal container is said to be malleable. Some metals tend to be quite malleable. This is mainly due to the structure of the atom. If we revisit a previous topic where we talked about how particles were arranged in a solid, liquid or gas, we saw that particles in a solid are close in proximity, and can only vibrate and slide past each other without significant resistance or breaking any bond. Basically, the metal is not forced into any fixed orientation (as they are allowed to slide across each other). This explains why metals are malleable.