let us energy to learn lettuce energy we have to compare it with daily life example let's consider that you are going to cook macaroni we all know that you will cook it step by step for example you boil the macaroni secondly you take the chicken you cut it into small pieces and you fry them thirdly you take some vegetables you cut them into small pieces and you fry them lastly you mix them all and your macaroni is ready now listen carefully when you boil the macaroni you provide some sort of heat energy let you provide 40 joule energy to eat similarly when you fry the chicken pieces you also provide some sort of heat energy let you provide 80 joule energy to eight also you provide energy when you fry the vegetables that you provide 70 joule energy finally you get the delicious food of macaroni remember that macaroni release heat energy when it is cooled down therefore we say that energy is required with each and every step of cooking macaroni now let's consider sodium chloride if i ask you to prepare sodium chloride how you will do it well we know that sodium is a metal and it exists in solid state while chlorine is a non-metal and it exists in gaseous form as a molecule firstly we need to convert sodium into small pieces i mean we will convert sodium from solid state to sodium and to gaseous state remember that when we convert sodium atom from solid state to gaseous state the energy absorbed is called heat of sublimation secondly we need to fry gaseous sodium atom i mean we will remove one electron from it to make it positive sodium ion remember that when we provide a minimum energy to the gaseous atom to lose one electron and become positive ion this energy is called as ionization energy similarly chlorine gas contains two atoms we will cut it into two small pieces i mean we will isolate or separate the two atoms of chlorine remember that the energy needed to break the bond of chlorine molecule is called dissociation energy lastly chlorine gas will gain this electron to become negative chlorine ion remember that when a gaseous atom gain an electron to form negative ion the energy released is called as electron affinity now every ingredient is ready let's mix them all so this positive ion of sodium and this negative ion of chlorine will combine together to form one mole of sodium chloride so we have successfully cooked or successfully prepared one mole of sodium chloride in the previous example just like cooking macaroni where energy was required at each and every step similarly energy is required at each and every step of preparing sodium chloride now listen carefully when sodium iron and chlorine iron combine together to form one mole of sodium chloride in this last stage they release 786 kilo joule per mole energy which is known as lattice energy so this energy is the latest energy therefore we define lattice energy as the energy released when gaseous iron react together to form one mole of ionic compound let me repeat it the energy released when gaseous ions react together to form one mole of ionic compound so this is the basic definition of lettuce energy now if you ask me why sodium ion and chlorine iron release energy when they are combined together well the answer is simple sodium ion and chlorine iron are unstable because they have high energy they want to lower their respective energies by combining together when they combine together they become stable and they release energy which is known as lettuce energy therefore remember that lettuce energy is the energy released when ionic bond is formed between two gaseous ions now let me teach you one important question which a lot of students are missing is lattice energy an endothermic or exothermic process well the simple and quick answer is both lettuce energy is exothermic process as well as endothermic process for example we have already learned that when gaseous sodium ion reacts with gaseous chlorine iron to form one mole of sodium chloride they release minus 786 kilojoule per mole energy this energy is called latest energy now in this case energy is released into the surrounding so we say that latest energy is exothermic process secondly consider this lattice of sodium chloride are this three-dimensional structure of sodium chloride now i am interested to break this lettuce into sodium ions and chlorine ions i will give the same amount of energy which it has already released and to the surrounding i mean i will give positive 786 kilojoule per mole energy to this lettuce to break it into sodium ions and chlorine ions remember that this energy is also called as lattice energy this time energy is absorbed from the surrounding so we say that lattice energy is endothermic process therefore remember that lattice energy is endothermic as well as exothermic process and the sign of lattice energy is both positive and negative remember this very very important point latest energy is the energy released when one mole of ionic compound is formed from gaseous ions our lattice energy is the energy absorbed to break one mole of ionic compound and to the gaseous ions so remember these two definitions of lettuce energy which many students do not understand finally let me teach you one bonus concept what is the difference between lettuce energy and heta formation well when sodium ion in gaseous stead and chlorine ion in gaseous state react together to form sodium chloride they release 786 kilojoule per mole energy which is known as lattice energy on the other hand when sodium atom and solid state are pure state react with one chlorine atom and gaseous state to form sodium chloride they also release 411 kilojoule per mole energy this energy is known as heat of formation or enthalpy of formation secondly in case of latest energy both the reactants have the same physical state while in case of heat affirmation the reactants have different physical state thirdly in case of lattice energy the reactants are ions having opposite charge while in case of heat affirmation reactants are usually elements having no charge thus these are the main differences between lattice energy and heter formation i hope that you have learned all about lettuce energy