Indietro
Problema 86a
(a) Describe what is meant by an electron-deficient molecule.
Problema 86b
(b) Describe what is meant by a three-center, two-electron bond.
Problema 87
Suggest a structure for the mixed aluminum–boron hydride AlBH6.
- Identify the group 4A element that best fits each of the following descriptions: (a) Prefers the +2 oxidation state; (d) Forms the most acidic oxide.
Problema 88
Problema 88b
Identify the group 4A element that best fits each of the following descriptions.
(b) Forms the strongest π bonds
Problema 88c
Identify the group 4A element that best fits each of the following descriptions.
(c) Is the second most abundant element in the Earth's crust
Problema 89
Select the group 4A element that best fits each of the following descriptions.
(c) Is the second most abundant element in the human body
- What is the shape of each of the following molecules or ions, and which hybrid orbitals are used by the central atom? (a) SiO₄⁴⁻ (b) CCl₄ (c) SnCl₂ (d) HCN
Problema 91
- Describe the preparation of silicon from silica sand, and explain how silicon is purified for use in semiconductor devices. Write balanced equations for all reactions.
Problema 97
- How do the structures and properties of elemental silicon and germanium differ from those of tin and lead?
Problema 98
- Write balanced equations for the formation of the following compounds from their elements. (c) Uranium hexafluoride (a solid at 25 °C)
Problema 102
- The organ pipes in unheated northern European churches are often observed to be pitted and crumbling to powder in places. Suggest an explanation, given that the pipes are made from tin.
Problema 103
- Identify the group 5A element(s) that best fit each of the following descriptions: (a) Makes up part of bones and teeth, (c) Is the most abundant element in the atmosphere, (d) Forms a basic oxide.
Problema 104
- Identify the group 5A element that best fits each of the following descriptions: (a) Forms oxides with the group 5A element in the +1, +2 and +4 oxidation states, (b) Is a metal, (c) Is the most abundant group 5A element in the Earth’s crust.
Problema 105
Problema 105a
Identify the group 5A element that best fits each of the following descriptions.
(a) Forms strong π bonds
- Give the chemical formula for each of the following compounds, and indicate the oxidation state of the group 5A element: (a) Nitrous oxide (b) Hydrazine (c) Calcium phosphide (d) Phosphorous acid (e) Arsenic acid.
Problema 106
- Give the chemical formula for each of the following compounds, and indicate the oxidation state of the group 5A element. (a) Nitric oxide (b) Nitrous acid (c) Phosphine (d) Phosphoric acid
Problema 107
- Draw an electron-dot structure for N2, and explain why this molecule is so unreactive.
Problema 108
- Assign oxidation numbers to each element in the following ions. (c) C2O4 2-
Problema 110
- Draw the structure of each of the following molecules: (a) Tetraphosphorus hexoxide, (b) Tetraphosphorus decoxide, (c) Phosphorous acid, (d) Phosphoric acid.
Problema 111
- Account for each of the following observations: (b) Phosphorous acid is a diprotic acid.
Problema 112
- Draw all the possible resonance structures for N2O and assign formal charges. Which resonance structure makes the greatest contribution to the resonance hybrid?
Problema 114
Problema 115
Could the strain in the P4 molecule be reduced by using sp3 hybrid orbitals in bonding instead of pure p orbitals? Explain.
- Identify the group 6A element that best fits each of the following descriptions: (a) Is the most electronegative, (b) Is a semimetal, (c) Is radioactive, (d) Is the most abundant element in the Earth’s crust.
Problema 116
- Identify the group 6A element that best fits each of the following descriptions: (a) Is a metal, (b) Is the most abundant element in the human body, (c) Is the strongest oxidizing agent, (d) Has the most negative electron affinity.
Problema 117
- Write a balanced equation for the reaction of an excess of O2 with each of the following elements: (a) Ca (b) C (c) As (d) B.
Problema 121
- If an element forms an acidic oxide, is it more likely to form an ionic or covalent hydride?
Problema 122
- If an element forms an ionic hydride, is it more likely to form an acidic or basic oxide?
Problema 123
Problema 124
Arrange the following oxides in order of increasing covalent character: B2O3, BeO, CO2, Li2O, N2O5.
- Arrange the following oxides in order of increasing ionic character: SiO2, K2O, P4O10, Ga2O3, GeO2.
Problema 125