Problem 74
What is the trend in ionization energy when proceeding down a group in the periodic table. Rationalize this trend.
Problem 75
(a) Explain why the sizes of atoms change when proceeding across a period of the periodic table. (b) Explain why the sizes of transition metal atoms change very little across a period.
Problem 76
Which of the following elements has the greatest difference between its first and second ionization energies: \(\mathrm{C}, \mathrm{Li}, \mathrm{N},\) Be? Explain your answer.
Problem 77
A What arguments would you use to convince another student in general chemistry that \(\mathrm{MgO}\) consists of the ions \(\mathrm{Mg}^{2+}\) and \(\mathrm{O}^{2-}\) and not the ions \(\mathrm{Mg}^{+}\) and \(\mathrm{O}^{-2}\). What experiments could be done to provide some evidence that the correct formulation of magnesium oxide is \(\mathrm{Mg}^{2+} \mathrm{O}^{2-} ?\)
Problem 78
Explain why the first ionization energy of Ca is greater than that of \(K\), whereas the second ionization energy of Ca is lower than the second ionization energy of K.
Problem 80
A The ionization energies for the removal of the first electron in \(\mathrm{Si}, \mathrm{P}, \mathrm{S},\) and \(\mathrm{Cl}\) are as listed in the table below. Briefly rationalize this trend.
Problem 81
Using your knowledge of the trends in element sizes on going across the periodic table, explain briefly why the density of the elements increases from K through V.
Problem 83
The discovery of two new elements (atomic numbers 113 and 115 ) was announced in February 2004. (a) Use spáf and noble gas notations to give the electron configurations of these two elements. (b) For each of these elements, name another element in the same periodic group. (c) Element 113 was made by firing the nucleus of a light atom at a heavy americium atom. The two nuclei combine to give a nucleus with 113 protons. What light atom was used as a projectile?
Problem 84
Explain why the reaction of calcium and fluorine does not form \(\mathrm{CaF}_{3}\)
Problem 86
Sodium metal reacts readily with chlorine gas to give sodium chloride. $$ \mathrm{Na}(\mathrm{s})+1 / 2 \mathrm{C}_{2}(\mathrm{g}) \rightarrow \mathrm{NaCl}(\mathrm{s}) $$ (a) What is the reducing agent in this reaction? What property of the element contributes to its ability to act as a reducing agent? (b) What is the oxidizing agent in this reaction? What property of the element contributes to its ability to act as an oxidizing agent? (c) Why does the reaction produce NaCl and not a compound such as \(\mathrm{Na}_{2} \mathrm{Cl}\) or \(\mathrm{NaCl}_{2} ?\)
