1.
Which of the following is hydrophobic?
Correct Answer
A. A. Molecules containing non-polar covalent bonds only
Explanation
Molecules containing non-polar covalent bonds only are hydrophobic because they do not have a charge and cannot form hydrogen bonds with water molecules. Hydrophobic molecules are repelled by water and tend to be insoluble in water.
2.
In a non-polar covalent bond:
Correct Answer
B. B. the two atoms forming the bond have the same affinity for electrons.
Explanation
In a non-polar covalent bond, the two atoms forming the bond have the same affinity for electrons. This means that neither atom has a greater attraction for the shared electrons, resulting in an equal sharing of electrons between the atoms. As a result, there are no partial charges on the atoms forming the bond, and the bond is not held together by opposing charges.
3.
A covalent bond is most likely to form between:
Correct Answer
D. D. two atoms, both of which typically become stable by gaining an electron.
Explanation
A covalent bond is formed when two atoms share electrons in order to achieve stability. In this case, both atoms are described as typically becoming stable by gaining an electron. This suggests that both atoms have a tendency to gain an electron in order to achieve a full outer electron shell. Therefore, it is most likely that a covalent bond would form between two atoms that both typically become stable by gaining an electron.
4.
An ionic bond is most likely to form between:
Correct Answer
C. C. a negatively and a positively charged ion.
Explanation
An ionic bond is formed when there is a transfer of electrons from one atom to another, resulting in the formation of ions. In this case, a negatively charged ion (anion) and a positively charged ion (cation) are required to form an ionic bond. This is because the positively charged ion will have a tendency to donate electrons, while the negatively charged ion will have a tendency to accept electrons. Therefore, option C, which states that an ionic bond is most likely to form between a negatively and a positively charged ion, is the correct answer.
5.
Which of the following atoms is a negatively charged ion?
Correct Answer
A. A. An atom that becomes stable by gaining an electron
Explanation
A negatively charged ion is formed when an atom gains one or more electrons. By gaining an electron, the atom becomes negatively charged because the number of electrons exceeds the number of protons, resulting in a net negative charge. This process allows the atom to achieve a stable electron configuration similar to that of a noble gas. Therefore, option A is the correct answer as it describes an atom that becomes stable by gaining an electron.
6.
Which of the following electrons has the most energy?
Correct Answer
C. C. An electron that is in a shell relatively distant from the nucleus
Explanation
An electron that is in a shell relatively distant from the nucleus has the most energy because electrons in higher energy levels are further away from the attractive force of the nucleus and experience less electrostatic attraction. As a result, they are less tightly bound to the nucleus and have more energy.
7.
Which of the following carries a negative charge?
Correct Answer
C. C. An electron
Explanation
An electron carries a negative charge. Electrons are subatomic particles that orbit around the nucleus of an atom. They have a fundamental negative charge and are responsible for the flow of electricity in conductors. Protons, on the other hand, carry a positive charge, while neutrons have no charge. The nucleus is the central part of an atom that contains protons and neutrons, but it does not carry a charge itself.
8.
The most basic unit of an element is:
Correct Answer
A. A. a proton.
Explanation
The most basic unit of an element is an atom, which is composed of protons, neutrons, and electrons. While a proton is one of the components of an atom, it is not the most basic unit itself.