Use the Born-Haber cycle to calculate the lattice energy of KF. [The heat of sublimation of K is 91.6 kJ·mol−1 and  ΔfH(KF) = −567.3 kJ·mol−1.  Bond enthalpy for F2 is  158.8 kJ·mol−1.  Other data may be found in the Ionization Energies Table and the Electron Affinities Table.]

Consider the following compounds: CaCl 2 , CaI 2 , and MgCl 2 . Answer the following questions based on expected periodic trends: (a) Which is expected to have t he shortest ionic bonds? (b) Which is expected to have the highest lattice energy? (c) Which is expected to have the lowest melting point?

Lewis structures of group W compounds Draw Lewis structures for each of the following molecule or ion: Nitrogen, N2 Hydrogen cyanide, HCN Hydronium ion, H30* • lodine, I2 Ammonium, NH4* Formaldehyde, CH20

Draw the Lewis structure for the chlorine pentafluoride (CIF) molecule. Ċ с X C 0

Keeping in mind that some elements violate the octet rule, draw a Lewis structure for each compound: (a) BCl 3; (b) SO 3.

10.) The structural formula of a certain aldehyde (related to formaldehyde) is H3C-CH2-CHO.  Draw a Lewis structure for this aldehyde and determine the number of bonds present.  Note that a single or a double or a triple bond counts as one bond. Write the number, not the word.

Use electronegativity values to classify each bond as nonpolar, polar covalent, or ionic: (a) Cl 2; (b) HCl; (c) NaCl.

Write the Lewis symbols and structures that show how BaBr2 forms from barium and bromine atoms.

Write Lewis dot symbols for (a) fluoride ion (F−), (b) potassium ion (K+), and (c) sulfide ion (S2−).