Respuesta :
Answer:
- Born-Haber cycle is consist on four to five steps. 1: ionization energy 2: electron affinity 3: dissociation energy 4: sublimation energy and last is Hess law.
- Nitrate ion have 3 localized sigma bonds and 1 delocalized pie bond according to the resonance structure.
Explanation:
Step 1: NaCl(s) → Na(s) + 1/2 Cl2(g) ΔHf (ionization energy) in this step energy is required to change the phase of the compound
Step 2: Na(s) + 1/2 Cl2(g) → Na(g) + 1/2 Cl2(g) ΔHa (elements needed to be in gaseous state for born-haber cycle so metal changes from solid to gas state by changing the enthalpy.
Step 3: Na(g) + 1/2 Cl2(g) → Na(g) + Cl (g) 1/2ΔHd
Step 4: Na(g) + Cl(g) → Na⁺(g) + Cl⁻(g) IE+EA ( in this step both ionization energy and electron affinity was involved because in metal (Na) electron is added which needs the energy and this energy draw from the step 3 and Chlorine require releasing electron to be in ionic state so when electron leaves the orbit energy releases.
Step 5: final step is Hess Law which is the combination of all the steps which step 4 again go back to step 5 and this cycle continues by repeating same steps Na⁺(g) + Cl⁻(g)→NaCl(s)
at this step heat of formation is calculated
Heat of formation= atomization energy+ dissociation energy+ sum of ionization energies + sum of electron affinity + lattice energy.
2: if we look at the electron configuration of the nitrogen it has 5 electrons in its outermost shell which indicates it can make 5 bonds 4 bonds and 1 lone pair usually and Oxygen has 6 electrons in its outermost shell. So nitrate ion have the total number of 24 electrons including the 1 electron which shows on the compound.
So when they make nitrate ion NO₃⁻¹ it shows that nitrate has 3 resonance structures. Nitrogen's three sigma bonds are attached to oxygen and fourth one make 1 pie bond which can rotate, delocalized and change its position anytime from one Oxygen atom to other oxygen atom.
