Problem 13
Arrange the following molecules from most to least polar and explain your order: \(\mathrm{CH}_{4}, \mathrm{CF}_{2} \mathrm{C} \mathrm{l}_{2}, \mathrm{CF}_{2} \mathrm{H}_{2}, \mathrm{CCl}_{4},\) and \(\mathrm{CCl}_{2} \mathrm{H}_{2}\).
Problem 14
Does a Lewis structure tell which electrons come from which atoms? Explain.
Problem 15
True or false? In general, a large atom has a smaller electronegativity. Explain.
Problem 16
What is the central idea of the VSEPR model?
Problem 18
Most atoms in nature are found bonded together to form compounds instead of existing as individual atoms. Why is this true?
Problem 20
Describe the type of bonding that exists in the \(\mathrm{F}_{2}(g)\) molecule. How does this type of bonding differ from that found in the \(\mathrm{HF}(g)\) molecule? How is it similar?
Problem 21
Some plant fertilizer compounds are \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}, \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\) \(\mathrm{K}_{2} \mathrm{O}, \mathrm{P}_{2} \mathrm{O}_{5},\) and \(\mathrm{KCl}\) . Which of these compounds contain both ionic and covalent bonds?
Problem 22
Some of the important properties of ionic compounds are as follows: i. low electrical conductivity as solids and high conductivity in solution or when molten ii. relatively high melting and boiling points iii. brittleness iv. solubility in polar solvents How does the concept of ionic bonding discussed in this chapter account for these properties?
Problem 23
What is the electronegativity trend? Where does hydrogen fit into the electronegativity trend for the other elements in the periodic table?
Problem 24
Give one example of a compound having a linear molecular structure that has an overall dipole moment (is polar) and one example that does not have an overall dipole moment (is nonpolar). Do the same for molecules that have trigonal planar and tetrahedral molecular structures.
