Chemguide: Support for CIE A level Chemistry Learning outcome 23: Chemical energetics 23.1: Lattice energy and Born-Haber cycles Learning outcomes 23.1.1 and 23.1.5 Before you go on, find and read these statements in your syllabus. Statement 23.1.1(a) defines enthalpy change of atomisation. You will find enthalpy change of atomisation on the Chemguide page lattice enthalpy (lattice energy). For now just read the short section about atomisation enthalpies about a third of the way down the page. The rest of the page is relevant to the next section below. Statement 23.1.1(b) introduces lattice energy and statement 23.1.5 looks at the factors affecting it. You will find lattice enthalpies on the Chemguide page lattice enthalpy. CIE want you define lattice enthalpy as the exothermic change from gaseous ions to solid crystal - what I have defined as "lattice formation enthalpy". This page also includes an introduction to the calculations you will need for statement 23.1.4. It would be better to leave this until you come to that statement.
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