Rationalize the following lattice energy values: $$\begin{array}{|lc|} \hline & \text { Lattice Energy } \\ \text { Compound } & \text { (kj/mol) } \\ \hline \text { CaSe } & -2862 \\ \text { Na }_{2} \text { Se } & -2130 \\ \text { CaTe } & -2721 \\ \text { Na }_{2} \text { Te } & -2095 \\ \hline \end{array}$$

For each of the given compounds, identify the cations (positively charged ions) and anions (negatively charged ions) that make up the compound. 1. CaSe: Calcium ion (Ca^2+) and Selenide ion (Se^2-) 2. Na2Se: Sodium ion (Na^+) and Selenide ion (Se^2-) 3. CaTe: Calcium ion (Ca^2+) and Telluride ion (Te^2-) 4. Na2Te: Sodium ion (Na^+) and Telluride ion (Te^2-)

Having identified the ions in the compounds, we can now analyze how the ionic charges affect the lattice energies. The lattice energy of an ionic compound is directly proportional to the product of the charges of the cations and anions. In other words, greater charges on the ions will result in a higher lattice energy magnitude. Comparing the compounds, we see that: 1. CaSe and Na2Se have the same anion, Se^2-. However, Ca^2+ has a higher charge than Na^+. Therefore, CaSe will have a higher lattice energy magnitude compared to Na2Se. 2. Similarly, CaTe and Na2Te have the same anion, Te^2-. Ca^2+ has a higher charge than Na^+, so CaTe will have a higher lattice energy magnitude compared to Na2Te.

Now, let's analyze how the ionic radii (the distance between the ions) affect lattice energy. Lattice energy is inversely proportional to the distance between the ions. In simpler terms, larger ionic radii will result in lower lattice energy magnitudes. In this case, we're comparing the lattice energies of compounds having the same cations, namely CaSe and CaTe, and Na2Se and Na2Te. 1. Se^2- and Te^2- lie in the same group in the periodic table, with Te^2- being below Se^2-. The ionic radii of anions increases as we move down a group. Thus, Te^2- has a larger ionic radii than Se^2-. Hence, between CaSe and CaTe, the compound containing Te^2- (CaTe) will have a lower lattice energy magnitude compared to the compound containing Se^2- (CaSe). 2. Similarly, between Na2Se and Na2Te, the compound containing Te^2- (Na2Te) will have a lower lattice energy magnitude compared to the compound containing Se^2- (Na2Se).

To rationalize the given lattice energy values, we have analyzed the effects of ionic charge and ionic radii on the lattice energy magnitudes. The results of our analysis are consistent with the given values: CaSe has a higher lattice energy magnitude than Na2Se, CaTe has a higher lattice energy magnitude than Na2Te, and each compound containing Te^2- (CaTe and Na2Te) has a lower lattice energy magnitude compared to the corresponding compound containing Se^2- (CaSe and Na2Se).