Exploring Covalent Bonds: A Hands-On Guide with Fluorine, Hydrogen, and Oxygen, Study notes of Chemistry

Download Exploring Covalent Bonds: A Hands-On Guide with Fluorine, Hydrogen, and Oxygen and more Study notes Chemistry in PDF only on Docsity! Covalent Bonds Exploration Guide “I'll have my bond, speak not against my bond, I have sworn an oath that I will have my bond,” said Shylock in Shakespeare's The Merchant of Venice. Though Shylock was not an atom of fluorine, he could be speaking for one. His words ring true for fluorine and its strong inclination to form chemical bonds. Single fluorine atoms are even more unstable than Shylock's character. In fact, single fluorine atoms are never found alone in nature. Fluorine atoms have a strong tendency to form bonds and will react strongly with other substances to form ionic or covalent compounds. An atom is most stable when it has a full outer energy level, or valence. For most atoms, a full outer energy level contains 8 valence electrons. In a covalent bond, two atoms share a pair of electrons. The two electrons in that pair act as if they are in the outer energy level of both atoms at the same time, helping each atom to achieve a full outer energy level. Creating Covalent Molecules • Go to http://www.explorelearning.com/ • Log-In using your username and password (if you are not currently logged-in) • Find the Covalent Bonds Gizmo & click on “Lauch Gizmo” (be patient as it loads) In this Gizmo, you will build covalent molecules. You will choose a molecule to build, and then share two electrons between a pair of atoms to create a covalent chemical bond. 1. In the Gizmo, check that Fluorine is selected from the Select a substance dropdown menu at top right. From the left fluorine atom on the SIMULATION pane, choose an electron from the outer energy level, also known as a valence electron. Click on the electron and drag it to the other fluorine atom. Click Play. a. Observe what happens, and write down any changes you notice in the orbits of the electrons. How many electrons are in the shared orbit (the oblong one)? b. Click Pause, and move an electron from the outer energy level of the right atom to the left atom. Click Play. How many electrons are in the shared orbit now? c. An atom is most stable when its outer energy level is filled with electrons. For most atoms, the outer energy level can hold 8 electrons. Look at the left-hand fluorine atom. How many electrons are orbiting only the left-hand atom's nucleus (on the circular path)? Including the shared electrons, how many total electrons are orbiting the left-hand nucleus? d. Count the total electrons orbiting the right-hand fluorine nucleus. Do both atoms have a full complement of 8 orbiting electrons? Click Check to verify that you have correctly created a molecule of fluorine (F2). In reality, the orbits of electrons are more complex than what is shown, but the effects on valence are the same. e. A useful way to represent covalent bonds is a Lewis diagram. In the DESCRIPTION pane, select the Show Lewis diagram checkbox. The diagram represents a stable fluorine molecule. How many dots are drawn around the left-hand F? What do you think these dots represent? What is represented by the line between the two F's? 2. Click Pause, and choose Hydrogen from the Select a substance menu. Hydrogen is a unique element because it forms stable covalent bonds with only two electrons orbiting the nucleus. Be sure the Show Lewis diagram box is checked. a. Examine the Lewis diagram in the DESCRIPTION pane. Compared to the diagram of the fluorine molecule, what seems to be missing? How many electrons are represented by the line between the two H's? b. Drag electrons between the atoms to create a hydrogen molecule, H2, and click Play. Click Check to test your configuration. If necessary, repeat the process until you are correct. (You can click Reset to start over.) c. How many electrons are orbiting each hydrogen atom? How is that different from what you observed when you built a fluorine molecule?