.Draw the born-Haber lattice energy cycle for sodium chloride. Explain the concept of resonance using the nitrate ion 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.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.