英語長文問題クエスト Part 24 (テーマ：化学)

英語の読解力を伸ばすには多読が必須！特に、TOEFL ibt というテストでは、かなり高度な読解力が必要ですし、何より、このTOEFL ibt という試験が難しいことの理由の１つに、日本語でも勉強していないアカデミックな内容の文章が出題されることです。
このクエストを進めれば、英語の読解力と知識を同時にアップデートさせられるでしょう！
さぁ、今日のクエストを進めてみましょう！

Passage

Title: Chemical Bonds and Molecular Structure

Chemical bonds are the forces that hold atoms together to form molecules and compounds. Understanding the nature of chemical bonds is essential to understanding the behavior of matter at the molecular level.

The most common type of chemical bond is the covalent bond, which occurs when two atoms share electrons in order to achieve a more stable electron configuration. Covalent bonds can be polar or nonpolar, depending on the distribution of electrons between the two atoms. In a polar covalent bond, the electrons are shared unequally, resulting in a partial positive charge on one atom and a partial negative charge on the other. In a nonpolar covalent bond, the electrons are shared equally between the two atoms.

Ionic bonds are another important type of chemical bond. Ionic bonds occur when one atom donates one or more electrons to another atom, resulting in the formation of positive and negative ions that attract each other. Ionic compounds, such as sodium chloride, are formed when metals and nonmetals react to form ions that are held together by ionic bonds.

Metallic bonds are a third type of chemical bond. Metallic bonds occur when metal atoms share their outer electrons with many neighboring atoms, resulting in a sea of electrons that are free to move throughout the metal. This accounts for many of the unique properties of metals, such as their high electrical and thermal conductivity.

The structure of a molecule is determined by the arrangement of its atoms and the bonds between them. The VSEPR (Valence Shell Electron Pair Repulsion) theory is a useful tool for predicting the shape of a molecule based on the number of electron pairs surrounding the central atom. This theory predicts that electron pairs in the valence shell of an atom will repel each other and will arrange themselves as far apart as possible to minimize this repulsion. The resulting shape of the molecule will depend on the number of electron pairs and the spatial arrangement of these pairs.

In conclusion, chemical bonds are the forces that hold atoms together to form molecules and compounds, and understanding their nature is essential to understanding the behavior of matter at the molecular level. Covalent, ionic, and metallic bonds are the most common types of chemical bonds, and the VSEPR theory is a useful tool for predicting the shape of molecules based on the number and arrangement of electron pairs around the central atom.

Questions

1. What is the most common type of chemical bond?
   A. Ionic bond
   B. Covalent bond
   C. Metallic bond
   D. Van der Waals bond

2. How do atoms achieve a more stable electron configuration?
   A. By sharing electrons in a covalent bond
   B. By donating electrons in an ionic bond
   C. By sharing their outer electrons in a metallic bond
   D. By attracting electrons in a van der Waals bond

3. What is the difference between a polar covalent bond and a nonpolar covalent bond?
   A. Polar covalent bonds involve unequal sharing of electrons, while nonpolar covalent bonds involve equal sharing of electrons.
   B. Polar covalent bonds involve the transfer of electrons, while nonpolar covalent bonds involve the sharing of electrons.
   C. Polar covalent bonds involve the attraction of opposite charges, while nonpolar covalent bonds involve the repulsion of similar charges.
   D. Polar covalent bonds involve the formation of ionic compounds, while nonpolar covalent bonds involve the formation of covalent compounds.

4. What is an ionic bond?
   A. An ionic bond occurs when two atoms share electrons in order to achieve a more stable electron configuration.
   B. An ionic bond occurs when metal atoms share their outer electrons with many neighboring atoms.
   C. An ionic bond occurs when one atom donates one or more electrons to another atom, resulting in the formation of positive and negative ions that attract each other.
   D. An ionic bond occurs when the electrons are shared equally between two atoms.

5. What is the VSEPR theory?
   A. The VSEPR theory is a theory that predicts the arrangement of atoms in a molecule based on the number of electron pairs surrounding the central atom.
   B. The VSEPR theory is a theory that explains how metal atoms share their outer electrons with many neighboring atoms.
   C. The VSEPR theory is a theory that explains how ionic compounds are formed.
   D. The VSEPR theory is a theory that explains how van der Waals bonds are formed.

6. What is the significance of the VSEPR theory?
   A. It explains the nature of chemical bonds.
   B. It predicts the shape of a molecule based on the number of electron pairs surrounding the central atom.
   C. It explains the properties of metals.
   D. It explains the behavior of matter at the molecular level.

7. Which of the following is not a type of chemical bond mentioned in the passage?
   A. Polar covalent bond
   B. Metallic bond
   C. Van der Waals bond
   D. Hydrogen bond

8. What is the structure of a molecule determined by?
   A. The arrangement of its atoms and the bonds between them.
   B. The number of electrons in the valence shell of an atom.
   C. The type of chemical bond that holds the atoms together.
   D. The properties of the central atom in the molecule.

9. What is the most unique property of metals?
   A. Their high electrical and thermal conductivity.
   B. Their ability to form ionic compounds.
   C. Their ability to share electrons in covalent bonds.
   D. Their ability to form van der Waals bonds.

10. How do electron pairs arrange themselves in a molecule according to the VSEPR theory?
    A. They arrange themselves as close together as possible to minimize repulsion.
    B. They arrange themselves as far apart as possible to minimize repulsion.
    C. They arrange themselves randomly around the central atom.
    D. They arrange themselves in a specific pattern that depends on the type of chemical bond involved.

Answers and Explanation