Comparing Bond Strength Name____Solutions______
Directions: Lattice energy is a measure of the strength of an ionic bond. It is the amount of energy released as the compound forms. The greater the amount of energy released, the stronger the bonds that form. Complete the table using the "Handbook of Chemistry and Physics". The energy values should be taken from the middle column and are found starting on page 12-13.
Chemical Formula / Charge on positive ion / Charge on negative ion / Smaller Radius (Positive Ion) / Smaller Radius (Negative Ion) / Lattice Energy (kJ/mol)BeF2 / 2+ / 1- / X / X / 3150
MgCl2 / 2+ / 1- / 2326
1. What effect does the size of the ions have on the lattice energy?
Smaller radius results in stronger bonds (greater lattice energy.)
Chemical Formula / Charge on positive ion / Charge on negative ion / Smaller Radius (Positive Ion) / Smaller Radius (Negative Ion) / Lattice Energy (kJ/mol)LiF / 1+ / 1- / same / same / 1030
BeO / 2+ / 2- / same / same / 4293
2. What effect does the charge of the ions have on the lattice energy?
Greater charge results in stronger bonds (greater lattice energy.)
Chemical Formula / Charge on positive ion / Charge on negative ion / Smaller Radius (Positive Ion) / Smaller Radius (Negative Ion) / Lattice Energy (kJ/mol)Na2O / 1+ / 2- / same / same / 2481
MgF2 / 2+ / 1- / same / same / 2913
3. When the overall charges and radii are the same, does the charge on the positive or negative ion seem to have a greater effect on lattice energy?
The charge on the positive ion has a greater effect on lattice energy.
Chemical Formula / Charge on positive ion / Charge on negative ion / Smaller Radius (Positive Ion) / Smaller Radius (Negative Ion) / Lattice Energy (kJ/mol)MgSe / 2+ / 2- / same / same / 3071
AlBr3 / 3+ / 1- / same / same / 5247
4. When the total charges and radii are the same, but the individual charges are different (3+ and 1- vs. 2+ and 2-), what seems to be the determining factor for lattice energy?
The greatest individual charge produces the strongest bonds (greatest lattice energy.)
Circle the compound in each pair with the highest melting point (think about lattice energy). Give a brief explanation for why you chose the one you did.
5. LiOH KOH Lithium has fewer energy levels than potassium.
6. ScN SnO Bigger charges on Sc and N.
7. Li2Se BeBr2 Greater charge on the positive ion.
Circle the compound in each pair with the lowest boiling point (think about lattice energy). Give a brief explanation for why you chose the one you did.
8. YI3 SrO Y has the greatest individual charge, so SrO has the
lower boiling point.
9. MnPO4 Ba(NO3)2 Smaller charges on the Ba and NO3 ions.
10. KHCO3 RbHCO3 More energy levels for Rb.
Circle the compound in each pair with the hardest crystals (think about lattice energy). Give a brief explanation for why you chose the one you did.
11. MgO FeCl3 Fe has the greatest individual charge.
12. (NH4)2S CaCO3 Bigger charge on Ca.
13. Fe2O3 FeO Bigger charge on the Fe in Fe2O3.