Question Video: Identifying the Statement That Describes How a Single Covalent Bond Is Formed between Hydrogen and Chlorine Atoms Science • First Year of Preparatory School

Video Transcript

The diagram shows a molecule of hydrogen chloride gas. Which statement correctly describes how a single covalent bond is formed between the two atoms? (A) The atoms share a pair of electrons, and both atoms gain a full outer shell. (B) The hydrogen atom transfers an electron to the chlorine atom, and both atoms gain a full outer shell. (C) The atoms share a pair of electrons, and only the chlorine atom gains a full outer shell. (D) The hydrogen atom transfers an electron to the chlorine atom, and both atoms have the same number of electrons in their outer shell. Or (E) the atoms share a pair of electrons, and both atoms have the same number of electrons in their outer shell.

The question tells us that the diagram shows us a molecule of hydrogen chloride gas. Hydrogen and chlorine atoms make up hydrogen chloride. Neutral hydrogen atoms have one electron. And neutral chlorine atoms have seven electrons in their outer shell. Each atom donates one outer-shell electron to form a single covalent bond. So two electrons are shared between both atoms. This means that chlorine now essentially has eight electrons in its outer shell, giving it a full outer shell of electrons. Hydrogen, when bonded to chlorine, has two outer-shell electrons. Thus, it also has a full outer shell.

We have determined that the atoms share a pair of electrons, forming a bond. And in doing so, both gain a full outer shell of electrons. Thus, the statement which correctly describes how a single covalent bond is formed between the two atoms is (A). The atoms share a pair of electrons, and both atoms gain a full outer shell.