Bonding and Molecular Structure
Explain each of the following observations in terms of electronic structure and/or bonding of the compounds involved.
(a) At ordinary conditions, HF (normal boiling point = 20C) is a liquid, whereas HCl (normal boiling point = -114C) is a gas
(b) Molecules of AsF3 are polar, whereas molecules of AsF5 are nonpolar.
(c) The N-O bonds in the NO2- ion are equal in length whereas they are unequal in HNO2
(d) For sulfur, the fluorides SF2, SF4, and SF6 are known to exist, where as for oxygen only OF2 is known to exist.
(e) Dimethyl ether, H3C-O-CH3, is not very soluble in water. Draw a structural isomer of dimethyl ether that is much more soluble in water and explain the basis of its increased water solubility.
(f) Selenium has six stable isotopes. In terms of atomic structure, explain what these isotopes have in common, and how they differ.
(g) In terms of atomic structure, explain why the first ionization energy of selenium is less than that of bromine but greater than tellurium
(h) Selenium reacts with fluorine to form SeF4. Draw the complete Lewis Dot and sketch the molecular structure. Indicate whether the molecule is polar or nonpolar.
(I) even though NH3 and CH4 have similar molecular masses, NH3 has a much higher normal boiling point.
(j) MgO melts at a much higher temperature than NaF.
(k) SO2 has a dipole moment while CO2 does not.