1.
What is a covalent bond?
Correct Answer
A. The bond formed by the sharing of a pair of electrons by two atoms
Explanation
A covalent bond is formed when two atoms share a pair of electrons. This type of bond occurs between nonmetal atoms and is characterized by the sharing of electrons in order to achieve a more stable electron configuration. Unlike an ionic bond, where electrons are transferred from one atom to another, covalent bonds involve the equal sharing of electrons between atoms. This sharing allows both atoms to have a full outer electron shell, resulting in a more stable and lower energy state.
2.
An ionic bond normally forms between...
Correct Answer
B. A metal and a nonmetal
Explanation
An ionic bond is a type of chemical bond that forms between a metal and a nonmetal. In this type of bond, electrons are transferred from the metal to the nonmetal, resulting in the formation of positively charged metal ions and negatively charged nonmetal ions. This attraction between opposite charges creates a strong bond between the two ions. Ionic bonds are typically formed between elements with large differences in electronegativity, which is why they commonly occur between metals and nonmetals.
3.
The melting and boiling point of an ionic compound are usually
Correct Answer
B. Very high
Explanation
Ionic compounds consist of positive and negative ions held together by strong electrostatic forces. These forces require a significant amount of energy to break, resulting in high melting and boiling points. Therefore, the correct answer is "very high."
4.
Covalent bonds usually occur between..
Correct Answer
A. Two nonmetals
Explanation
Covalent bonds typically occur between two nonmetals. In a covalent bond, atoms share electrons to achieve a stable electron configuration. Nonmetals have a higher electronegativity, meaning they have a greater tendency to attract electrons. When two nonmetals bond, they can share electrons equally or unequally, forming a covalent bond. This type of bond is common in molecules such as water (H2O) or carbon dioxide (CO2), where nonmetal atoms share electrons to complete their outer electron shells.
5.
At room temperature, covalent bonds are _____ while ionic bonds are _____.
Correct Answer
D. Liquid;solid
Explanation
At room temperature, covalent bonds are typically in the liquid state, while ionic bonds are typically in the solid state. This is because covalent bonds involve the sharing of electrons between atoms, which allows for more flexibility and movement, leading to a liquid state. On the other hand, ionic bonds involve the transfer of electrons from one atom to another, creating a strong electrostatic attraction between ions. This strong attraction results in a rigid lattice structure, leading to a solid state.
6.
Bond that has low melting and boiling points.
Correct Answer
C. Chemical Bond
Explanation
A chemical bond is the force of attraction between two atoms that holds them together in a molecule. It can be either ionic, metallic, or covalent. In this case, the bond described has low melting and boiling points, which suggests that it is a weak bond. Ionic and metallic bonds typically have high melting and boiling points due to their strong forces of attraction. Therefore, the most suitable explanation is that the bond in question is a chemical bond, which generally refers to covalent bonds that have lower melting and boiling points compared to ionic and metallic bonds.
7.
They require much more energy to break the bond between them.
Correct Answer
D. Ionic Bond
Explanation
Ionic bonds are formed between a metal and a non-metal. In this type of bond, electrons are transferred from the metal atom to the non-metal atom, resulting in the formation of positively charged metal ions and negatively charged non-metal ions. These oppositely charged ions are held together by strong electrostatic forces of attraction, which require a significant amount of energy to break. Therefore, ionic bonds require much more energy to break the bond between the ions compared to other types of chemical bonds.
8.
Ionic Bond is..
Correct Answer
D. The electrostatic bond between two ions formed through the transfer of one or more electrons
Explanation
Ionic Bond is the electrostatic bond between two ions formed through the transfer of one or more electrons. In an ionic bond, one atom donates electrons to another atom, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions). The attraction between these oppositely charged ions creates a strong bond. This type of bond is typically formed between a metal and a non-metal, as metals tend to lose electrons and non-metals tend to gain electrons. Ionic bonds are characterized by their high melting and boiling points and their ability to conduct electricity when dissolved in water.
9.
______ bonds are stronger bonds that have low melting and boiling points.
Correct Answer
Chemical
Explanation
Chemical bonds refer to the bonds formed between atoms in a chemical compound. These bonds can be either strong or weak, depending on the type of bond. In this case, the correct answer suggests that the stronger bonds have low melting and boiling points. This is because stronger bonds require more energy to break, resulting in higher melting and boiling points. Therefore, the statement implies that the given type of bonds, which are chemical bonds, are stronger and have low melting and boiling points.
10.
NaCl is an example of _______ bond.
Correct Answer
Ionic
Explanation
NaCl is an example of an ionic bond because it is formed between a metal (Na) and a nonmetal (Cl). In an ionic bond, one atom donates electrons to another atom, resulting in the formation of positively and negatively charged ions. In the case of NaCl, sodium (Na) donates an electron to chlorine (Cl), creating a positively charged sodium ion (Na+) and a negatively charged chloride ion (Cl-). These oppositely charged ions are then attracted to each other, forming an ionic bond.