Problem 95
The \(\mathrm{H}^{-}\) ion and the He atom have two \(1 \mathrm{~s}\) electrons each. Which of the two species is larger? Explain.
Problem 96
Predict the products of the following oxides with water: \(\mathrm{Na}_{2} \mathrm{O}, \mathrm{BaO}, \mathrm{CO}_{2}, \mathrm{~N}_{2} \mathrm{O}_{5}, \mathrm{P}_{4} \mathrm{O}_{10}, \mathrm{SO}_{3} .\) Write an equation for each of the reactions. Specify whether the oxides are acidic, basic, or amphoteric.
Problem 97
Write the formulas and names of the oxides of the second-period elements (Li to \(\mathrm{N}\) ). Identify the oxides as acidic, basic, or amphoteric. Use the highest oxidation state of each element.
Problem 98
State whether each of the following elements is a gas, liquid, or solid under atmospheric conditions. Also state whether it exists in the elemental form as atoms, molecules, or a three-dimensional network: \(\mathrm{Mg}, \mathrm{Cl}, \mathrm{Si},\) \(\mathrm{Kr}, \mathrm{O}, \mathrm{I}, \mathrm{Hg}, \mathrm{Br}\)
Problem 101
The atomic radius of \(\mathrm{K}\) is \(227 \mathrm{pm}\) and that of \(\mathrm{K}^{+}\) is \(138 \mathrm{pm} .\) Calculate the percent decrease in volume that occurs when \(\mathrm{K}(g)\) is converted to \(\mathrm{K}^{+}(g) .\) (The volume of a sphere is \(\frac{4}{3} \pi r^{3}\), where \(r\) is the radius of the sphere.)
Problem 103
Match each of the elements on the right with its description on the left: (a) A dark-red liquid (b) A colorless gas that burns in oxygen gas (c) A metal that reacts violently with water (d) A shiny metal that is used in jewelry (e) An inert gas Calcium (Ca) Gold \((\mathrm{Au})\) Hydrogen \(\left(\mathrm{H}_{2}\right)\) Argon (Ar) Bromine \(\left(\mathrm{Br}_{2}\right)\)
Problem 105
A student is given samples of three elements, \(X, Y,\) and \(\mathrm{Z}\), which could be an alkali metal, a member of Group 4A, or a member of Group 5A. She makes the following observations: Element \(\mathrm{X}\) has a metallic luster and conducts electricity. It reacts slowly with hydrochloric acid to produce hydrogen gas. Element \(Y\) is a light yellow solid that does not conduct electricity. Element \(Z\) has a metallic luster and conducts electricity. When exposed to air, it slowly forms a white powder. A solution of the white powder in water is basic. What can you conclude about the elements from these observations?
Problem 107
The ionization energies of sodium (in \(\mathrm{kJ} / \mathrm{mol}\) ), starting with the first and ending with the eleventh, are 496 , 4562,6910,9543,13,354,16,613,20,117,25,496 \(28,932,141,362,159,075 .\) Plot the log of ionization energy \((y\) axis \()\) versus the number of ionization \((x\) axis); for example, \(\log 496\) is plotted versus 1 (labeled \(I E_{1}\), the first ionization energy), \(\log 4562\) is plotted versus 2 (labeled \(I E_{2},\) the second ionization energy \(),\) and so on. (a) Label \(I E_{1}\) through \(I E_{11}\) with the electrons in orbitals such as \(1 s, 2 s, 2 p,\) and \(3 s\) (b) What can you deduce about electron shells from the breaks in the curve?
Problem 108
Explain, in terms of their electron configurations, why \(\mathrm{Fe}^{2+}\) is more easily oxidized to \(\mathrm{Fe}^{3+}\) than \(\mathrm{Mn}^{2+}\) is to \(\mathrm{Mn}^{3+}\)
Problem 109
Write the formulas and names of the hydrides of the following second-period elements: \(\mathrm{Li}, \mathrm{C}, \mathrm{N}, \mathrm{O}, \mathrm{F}\) Predict their reactions with water.
