Question

Draw Lewis dot structures for the molecules listed here. a. \(\mathrm{TeCl}_{2}\) b. \(\mathrm{HI}\) c. \(\mathrm{AsBr}_{3}\) d. \(\operatorname{SiF}_{4}\) e. \(\mathrm{F}_{2}\)

Short answer

To draw Lewis structures, connect atoms to form bonds; complete octets with the remaining electrons. Each structure is: - TeCl2 with Te in the center bonded to two Cl. - HI as a single bond. - AsBr3 with As central and bonded to three Br. - SiF4 with Si central bonded to four F. - F2 with a single bond between F atoms, completing octets.

Step-by-step solution

Understand the Components (TeCl2)

In this step, identify the number of valence electrons for the elements in iodine dichloride (TeCl2). Tellurium (Te) has 6 valence electrons, and each chlorine (Cl) has 7 valence electrons. Total electrons = 6 + 2(7) = 20.

Draw the Basic Skeleton (TeCl2)

Place tellurium in the center and attach the two chlorine atoms to it. This setup shows that Te is the central atom with single bonds connecting to each Cl.

Distribute the Electrons (TeCl2)

Complete the octets around the chlorine atoms first by placing six additional electrons (in three pairs) around each chlorine. Place the remaining electrons around the central Te to complete its octet.

Validate the Structure (TeCl2)

Ensure that each atom has a full octet. Te has 4 remaining valence electrons after bonding, which can complete its octet by being placed around it outside the bonds.

Analyze (HI)

Hydrogen (H) has 1 valence electron, and iodine (I) has 7 valence electrons. Total electrons = 1 + 7 = 8. Draw a single bond between H and I, using the remaining electrons to complete I's octet.

Assemble (AsBr3)

Arsenic (As) has 5 valence electrons, and each bromine (Br) has 7 valence electrons. Total = 5 + 3(7) = 26. Place As at the center and attach three Br atoms with single bonds; fill Br octets first.

Finalize Diphosphorus Trioxide (AsBr3)

Complete the octets for each Br atom by adding additional electron pairs. Remaining electrons are given to As. It should complete each atom's octet or Arsenic may have an expanded octet.

Detail (SiF4)

Silicon (Si) has 4 valence electrons, while each fluorine (F) has 7. Total = 4 + 4(7) = 32. Si is central; bond each F with single bonds. Each F achieves an octet with electrons added as pairs.

Validate (SiF4)

Ensure all fluorine atoms have octets. Silicon shares its electrons equally with F atoms, achieving stability. Total electron theory is satisfied.

Resolve (F2)

Fluorine (F) has 7 valence electrons. For F2, total = 2(7) = 14. Connect the atoms with a single bond and distribute the remaining electrons to fulfill the octets for each F atom.

Verify Completeness (F2)

Each F atom has a complete octet with the shared electrons in the single bond and three pairs of electrons surrounding it.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons in an atom that play a crucial role in forming chemical bonds. They are like the social butterflies of atoms, always on the lookout for friends, or rather, other electrons, to interact with. Here’s why they matter so much:

• Valence electrons determine an element's chemical properties and its reactivity.
• They participate in bond formation allowing atoms to achieve stable electron configurations.
• The number of valence electrons helps predict the bonding behavior of the atom.

For example, when we look at \( ext{TeCl}_2\), tellurium has 6 valence electrons, and each chlorine has 7. Together, they combine their valence electrons to form stable bonds.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms in a molecule. It is like understanding the shape of a tangled rope when you lift it up. This arrangement has significant implications on the molecule's properties and functions.

• The geometry affects physical properties such as boiling and melting points, as well as the reactivity.
• The shapes are governed by the number of bonding and non-bonding electron pairs around the central atom.
• Different molecules exhibit different geometries (e.g., linear, trigonal planar, tetrahedral) based on the amount of electron pairs.

In molecules like \( ext{AsBr}_3\), the arsenic atom is central with three bromine atoms forming a trigonal pyramidal shape due to lone pair-bonding pair interactions.

Octet Rule

The octet rule is a guiding principle for understanding how atoms bond together. It suggests that atoms tend to form bonds until they are surrounded by eight valence electrons, similar to noble gases that exude stability. Here's a deeper dive:

• Atoms achieve stability by acquiring a full set of 8 valence electrons.
• Exceptions to the rule include hydrogen, which follows the "duet rule", and elements like Phosphorus or Sulfur that can have expanded octets.
• The octet rule explains the types of bonds formed and why certain molecules, like \( ext{F}_2\), exhibit single bonds as they fulfill the octet criterion.

For \( ext{SiF}_4\), silicon shares its electrons with fluorine atoms, ensuring each achieves a full octet arrangement.

Chemical Bonds

Chemical bonds are the forces that hold atoms together in a compound. They are similar to glue for atoms, ensuring the structural integrity of molecules. Understanding bonds is essential to predict interactions and reactions.

• There are several types of chemical bonds: covalent, ionic, and metallic.
• Covalent bonds involve the sharing of electron pairs between atoms, typically seen in molecules like \( ext{HI}\).
• Ionic bonds result from the transfer of electrons from one atom to another, typically seen in compounds like sodium chloride.

In our tackle of \( ext{TeCl}_2\), the tellurium and chlorine atoms form single covalent bonds where they share electrons, maintaining the molecular structure necessary for stability.