Question

activity a: sharing electrons
get the gizmo ready:

• click reset.
• select hydrogen.

introduction: the electrons that orbit the nucleus of an atom are arranged into shells. the first shell contains up to two electrons and the second contains up to eight electrons. most elements are stable when they have eight valence electrons—a rule of thumb known as the octet rule. (elements with less than five electrons are stable with two valence electrons.)
question: what happens when atoms share electrons?

1. predict: each hydrogen atom has one valence electron, but it needs two electrons to be stable. how can both hydrogen atoms each achieve a stable configuration?
2. form a bond: drag the electrons so that they move around both hydrogen atoms. click play to observe them in orbit, and then click check. you have created a covalent bond.

congratulations, you have completed a molecule of hydrogen! because the molecule has two atoms, it is a diatomic molecule. click the camera ( ) icon to take a snapshot of your completed molecule. right - click the image, and click copy image. paste the image into a blank document and label the image “h₂.”

1. draw a diagram: covalent bonds are shown in lewis diagrams. in a lewis diagram, dots represent unshared valence electrons and dashes represent pairs of shared electrons.

turn on show lewis diagram. what is the lewis diagram for hydrogen, h₂? h h

1. form a bond: select fluorine and turn on highlight shared electrons. create a molecule of fluorine, f₂. take a snapshot of this molecule and add it to your document. (be sure to label each molecule you add.)

what is the lewis diagram for fluorine, f₂? f f

1. think and discuss: how is the formation of covalent bonds similar to kids sharing markers? how is it different? if possible, discuss your answer with your classmates and teacher.

Explanation:

Step1: Analyze hydrogen atom stability

Each hydrogen atom has 1 valence - electron and needs 2 to be stable. Two hydrogen atoms can share their single electrons.

Step2: Determine Lewis diagram for hydrogen

In a hydrogen molecule ($H_2$), the two hydrogen atoms share a pair of electrons. The Lewis diagram is $H - H$.

Step3: Analyze fluorine atom stability

Fluorine has 7 valence - electrons and needs 8 to be stable. Two fluorine atoms share a pair of electrons.

Step4: Determine Lewis diagram for fluorine

In a fluorine molecule ($F_2$), the Lewis diagram is $F:F$, where the colon represents the shared pair of electrons and each $F$ has 3 non - bonding pairs of electrons around it.

Step5: Compare covalent bond formation to sharing markers

Similarity: In both cases, resources (electrons or markers) are shared to achieve a more stable or useful state. For covalent bonds, atoms share electrons to achieve a stable electron configuration. Kids share markers to have access to more colors. Difference: Covalent bond formation is a chemical process based on the electrostatic forces between nuclei and electrons and is governed by quantum mechanical principles. Sharing markers is a social behavior based on human needs and cooperation.

Answer:

1. Two hydrogen atoms can share their single electrons to achieve a stable configuration with 2 electrons each.
2. The Lewis diagram for $H_2$ is $H - H$.
3. The Lewis diagram for $F_2$ is $F:F$ (with 3 non - bonding pairs of electrons around each $F$).
4. Similarity: Resources are shared to achieve a more stable or useful state. Difference: Covalent bond formation is a chemical process based on quantum mechanical principles, while sharing markers is a social behavior.