Chapter 8

Compare the elements Na, B, Al, and C with regard to the following properties: (a) Which has the largest atomic radius? (b) Which has the most negative electron affinity? (c) Place the elements in order of increasing ionization energy.

Two elements in the second transition series ( \(Y\) through Cd) have four unpaired electrons in their \(3+\) ions. What elements fit this description?

Why is the radius of \(\mathrm{Li}^{+}\) so much smaller than the radius of Li? Why is the radius of \(F^{-}\) so much larger than the radius of F?

Which ions in the following list are not likely to be found in chemical compounds: \(\mathbf{K}^{2+}, \mathbf{C s}^{+}, \mathbf{A l}^{4+}, \mathbf{F}^{2-},\) and \(\mathrm{Se}^{2-} ?\) Explain briefly.

Write electron configurations to show the first two ionization processes for potassium. Explain why the second ionization energy is much greater than the first.

Explain how the ionization energy of atoms changes and why the change occurs when proceeding down a group of the periodic table.

(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.

Which of the following elements has the greatest difference between its first and second ionization energies: \(\mathbf{C}\) Li, N, Be? Explain your answer.

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 \(\mathrm{K}\).

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 \(\mathrm{K}\) through \(\mathrm{V}\). (TABLE CANNOT COPY)

The discovery of two new elements (atomic numbers 113 and 115 ) was announced in February 2004 (IMAGE NOT COPY) (a) Use spdfand noble gas notations to give the electron configurations of these two elements. (b) Name an element in the same periodic group as the two elements. (c) Element 113 was made by firing a light atom at a heavy americium atom. The two combine to give a nucleus with 113 protons. What light atom was used as a projectile?

Explain why the reaction of calcium and fluorine does not form CaF \(_{3}\).

Sodium metal reacts readily with chlorine gas to give sodium chloride. (See General Chemistry Now CD-ROM or website Screen \(8.16 \text { Chemical Puzzler.})\) $$\mathrm{Na}(\mathrm{s})+\frac{1}{2} \mathrm{Cl}_{2}(\mathrm{g}) \longrightarrow \mathrm{NaCl}(\mathrm{s})$$ (a) What is the reducing agent in this reaction? What property of the element contributes to its ability as a reducing agent? (b) What is the oxidizing agent in this reaction? What property of the element contributes to its ability as an oxidizing agent? (c) Why does the reaction produce NaCl and not a compound such as \(\mathrm{Na}_{2} \mathrm{Cl}\) or \(\mathrm{NaCl}_{2} ?^{-}\)