![]() Because this process requires energy, it falls into the endothermic category, corresponding to a positive value. On the other hand, if we use the alternate definition, the dissolution of an ionic compound, the nature of the lattice energy value changes. Our first definition, the formation of an ionic compound, involves exothermic lattice energy, corresponding to a negative value. ![]() A process is exothermic when it releases energy. We can view lattice energies as either endothermic or exothermic processes depending on which definition we focus on. Depending on our chosen definition, the lattice energy of a given ionic compound may either be a positive or negative value. Lattice energy can be described as a certain quantity of energy is released when gaseous ions react during the formation of one mole of a solid ionic compound however, it also describes the energy that facilitates the dissociation of one mole of a solid ionic compound into its constituent gaseous ions. These interactions involve large amounts of energy, explaining the high melting and boiling points characteristic of ionic compounds. Their strong, rigid composition enables interactions between each charged ion and its oppositely charged counterparts. The key to understanding this concept lies in the crystalline structure of ionic compounds. We can further investigate this term in two different ways, depending on our perspective. Lattice energy maintains the fixed positions of cations and anions within ionic compounds. Both the generation and dissolution of such compounds involve the concept of lattice energy, a type of potential energy expressed in units of kJ/mol. Topics Covered in Other Articlesĭuring the formation of solid ionic compounds, electropositive metals react with electronegative nonmetals. Join my 1000+ subscribers on my YouTube Channel for new A Level Chemistry video lessons every week.In this tutorial about lattice energy, we will cover its definition, relevant periodic table trends, factors that influence it, and how to calculate it. Please LIKE this video and SHARE it with your friends! Found this A Level Chemistry video useful? Topic: Energetics, Physical Chemistry, A Level Chemistry, Singaporeīack to other previous Physical Chemistry Video Lessons. This expression is valid for all ionic compounds.įor the detailed step-by-step discussion on how to draw the Born Haber Cycle, check out this video! We can use the follow expression to work out the relationship of all the terms in the Born Haber cycle. Since strong ionic bonds are formed, lattice energy is highly exothermic. The last step involves lattice energy which is the forming of ionic compound from its constituent gaseous ions. ![]() First electron affinity is exothermic as energy is released from attraction formed between nucleus and added electron. Ionisation energy is endothermic as energy is required to overcome attraction between nucleus and valence electron.Īdding electron to Cl to form Cl - will be the first electron affinity of Cl. Removing 2 electrons from Ca to form Ca 2+ will be the first and second ionisation energies of Ca which can be found in the Data Booklet. Ionisation involves removing the electrons from Ca (ionisation energy) and adding electrons to Cl (electron affinity). Both terms are endothermic as energy is required to break all bonds in the elements to form gaseous atoms.įor Ca we will be given the enthalpy change of atomisation of metal.įor Cl 2 usually we use bond energy of Cl-Cl bond which can be found in the Data Booklet. We can draw this close to the bottom of the energy level diagram as the rest of the terms would be endothermic hence pointing upwards.Ītomisation involves forming gaseous atoms for both calcium metal and chlorine gas. Usually enthalpy change of formation for ionic compounds is exothermic as ionic compounds are stable. Formationįormation involves the reaction from elements in the standard state to ionic compound. We usually use the energy level diagram to present the Born Haber Cycle, which can be broken down into 4 steps. In this video we want to learn how to draw the Born Haber Cycle of ionic compounds using CaCl 2 as an example.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |