Selected alkali metals and halogens
Ionic radius and charge of alkali metals and halogens
Values of ∆Hatom, ∆Hie, ∆Hf, and ∆Hea of alkali metal halides
Difference of values using Born-Haber and Born-Lande formula
IB Data Booklet ver. 2016
Wired Chemist
Naukowiec
Google sheets
Scilearn Sydney Lattice energy calculator
It is assumed that the databases are performed in a safe environment. This investigation does not require any safety precautions since all of the procedures have already been performed by the database.
P R O C E D U R E S
1. Calculate the ionic sum, difference, and radius ratio between alkali metals and halogens.
2. Calculate the electronegativity difference between alkali metals and halogens.
3. Find experimental lattice enthalpies (using Born-Haber Cycle) from online databases
a. Collect lattice enthalpies directly from the IB Data Booklet, Wired Chemist, and Naukowiec
b. If some databases give values, use the formula below:
ΔHatom alkali metal + ΔHatom halogen + ΔHie alkali metal + ΔHea halogen + ΔHf alkali metal halides = ΔHlat
4. Use the formula (Born-Landé equation) below to find the theoretical lattice enthalpy:
E = Na M z+z– e2 / 4πε0r0(1−(1/n))
5. Calculate the percent difference between experimental and theoretical values:
(experimental − theoretical)/experimental × 100
6. Create a graph for MX lattices, comparing the electronegativity difference and ionic radii difference of experimental and theoretical lattice enthalpies;
a. X-axis: difference of electronegativity
b. Y-axis: difference of ionic radius
7. Create a graph for MX lattices, comparing the electronegativity difference and percent difference of experimental and theoretical lattice enthalpies;
a. X-axis: difference of electronegativity
b. Y-axis: percent difference of experimental and theoretical lattice enthalpy values
8. Create a graph for MX lattices, comparing the ionic radius difference and percent difference of experimental and theoretical lattice enthalpies;
a. X-axis: difference of ionic radius
b. Y-axis: percent difference of experimental and theoretical lattice enthalpy values