Chemistry alevel okra born hater cycle help please

For a Born-Haber cycle, say I was doing it with a group 3 chloride, I would need 3 atomisation energies of chlorine, 3 ionisation energies of the group 3 (e.g. Aluminium) and then 3 electron affiinities of chlorine?
For the atomisation energy of chlorine would it be
Al (s)+Cl3 (g)(standard states)
Al (s)+ Cl (g)
Al (s)+ 2Cl (g)
Al (s)+ 3Cl (g)

The atomisation energy of chlorine is
1/2 Cl2(g) —> Cl(g)
So three times it would be
3/2 Cl2(g) —> 3Cl(g)
Incidentally, the atomisation of aluminium would be
Al(s) —> Al(g)

So for the atomisation energies of just chlorine it would be:
Al (s) + 1/2 Cl2 (g)
Al (s) + Cl (g)
Al (s) + 2Cl(g)
Al (s) + 3Cl (g)
And then atomisation of Al would be Al (s) to Al (g)

I’d do all three atomisations of Cl in one step rather than write a series of equations. If you were to do each atomisation of chlorine in separate steps, you would have
Al(s) + 3/2 Cl2(g)
Al(s) + Cl2(g) + Cl(g)
Al(s) + 1/2 Cl2(g) + 2Cl(g)
Al(s) + 3Cl(g)
See how much more confusing that is?

Hi, I would do all three atomisation steps in one, this was just out of interest. So I was told by someone else it was
Al (s) + 1/2 Cl2 (g)
Al(s) + Cl (g)
Al(s) + 2Cl (g)
Al(s) + 3Cl(g)
Is that not correct then? This makes sense to me, I am in Alevels currently studying ing OCR A Chem. Could you explain your steps, I'm a little confused? Thank you so much!

The problem with that is that they have made two chlorine atoms appear out of nowhere, which breaks the law of conservation of mass. As such, you would need to start with 3/2 Cl2(g) rather than 1/2 Cl2(g) and making two more chlorines appear out of thin air.

Ohhhh, makes sense! Thank you
So for MgCl2 for example, would the atomisation energies of chlorine be
Mg (s) + Cl2 (g)
Mg (s) + 1/2Cl2 (g) + Cl (g)
Mg (s) + 2Cl (g)
Do you mind explaining this one too please? Thank you so much

Exactly. I’m not sure what there is left to explain about that particular example, but as you already realise it’s better to just combine all the atomisations of chlorine into one step rather than separate ones.
If you mean you want to look into how to construct the whole Born-Haber cycle for MgCl2, I’m more than happy to help with that.

Is there any other website that we could do this on, since I can't send images here. I'll type this one out but if you know any other websites please let me know 🙂 thank you for your help.
in the cycle, it would be a downward arrow if drawn out, connecting to bottom (MgCl2 (aq)) lattice enthalpy of MgCl2
in the cycle, it would be a downward arrow if drawn out- Mg2+ (g) +2 Cl- (g) first electron affinity of Cl x2
upward arrow- Mg 2+ (g) +2e- + 2Cl (g)2nd ionisation energy of Mg
upward arrow- Mg+ (g) + e- +2Cl- (g) first ionisation energy of Mg
upward arrow- Mg (g) + 2Cl (g)atomision energy of Mg
upward arrow- Mg (s) +Cl2 (g) atomisation energy of Cl
downward arrow- Mg (s) +Cl2 (g)- enthalpy of formation of Mgcl2
At bottom of cycle MgCl2(aq)