Problem 70 - Chemistry and Chemical Reactivity

Question

Consider the chemistries of \(\mathrm{C}, \mathrm{Si},\) Ge, and \(\mathrm{Sn} .\) (a) Write a balanced chemical equation to depict the reaction of each element with elemental chlorine. (b) Describe the bonding in each of the products of the reactions with chlorine as ionic or covalent. (You have not seen reactions of some of these elements in the text, but you have been given enough information to be able to predict the reactions that can occur.)

Step-by-Step Solution

Answer

Reactions: \( \mathrm{CCl}_4, \mathrm{SiCl}_4, \mathrm{GeCl}_4, \mathrm{SnCl}_4 \); all bonds are covalent.

Step 1: Understand the Reaction with Chlorine

Each element from the group, C, Si, Ge, and Sn, reacts with chlorine to form their respective chlorides. Chlorine, being a diatomic molecule \( \mathrm{Cl}_2 \), will react by accepting electrons from these elements to form chloro compounds.

Step 2: Write Balanced Chemical Equations

We write the balanced chemical equations for each reaction: - Carbon: \( \mathrm{C} + 2\mathrm{Cl}_2 \rightarrow \mathrm{CCl}_4 \)- Silicon: \( \mathrm{Si} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SiCl}_4 \)- Germanium: \( \mathrm{Ge} + 2\mathrm{Cl}_2 \rightarrow \mathrm{GeCl}_4 \)- Tin: \( \mathrm{Sn} + \mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_2 \) or \( \mathrm{Sn} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_4 \) The reactions depict the possible products with full coordination by chlorine atoms.

Step 3: Describe Bonding in Products

Now let's analyze the type of bond in each chloride compound produced. - \( \mathrm{CCl}_4 \), \( \mathrm{SiCl}_4 \), and \( \mathrm{GeCl}_4 \) form covalent bonds. This is because carbon, silicon, and germanium share electrons with chlorine.- \( \mathrm{SnCl}_2 \) primarily forms covalent bonds; however, \( \mathrm{SnCl}_4 \) has a more covalent character but could also have partial ionic character due to the metallic nature of tin.

Key Concepts

Group 14 Elements

Group 14 elements include carbon (C), silicon (Si), germanium (Ge), and tin (Sn). They are known for exhibiting a wide range of chemical behaviors due to their ability to form four bonds. This characteristic arises from having four electrons in their outermost shell. As a result, these elements can form compounds through either sharing or losing electrons.
This group is diverse in terms of physical properties. Carbon, for instance, is a non-metal, while silicon and germanium are metalloids. Tin, on the other hand, is a metal. These differences contribute to their varying reactivity and bonding tendencies in chemical reactions.

• Carbon forms strong covalent bonds and is a key component of organic chemistry.
• Silicon is widely used in electronics and forms covalent bonds.
• Germanium has properties similar to silicon but is less commonly used.
• Tin can participate in both covalent and ionic bonding due to its metallic property.

These elements react with chlorine by forming chlorides, showcasing their tendency to stabilize by completing their outer electron shells.

Chlorine Reactions

Chlorine is a reactive non-metal that exists as a diatomic molecule, \( \mathrm{Cl}_2 \). When reactants combine with chlorine, they tend to form compounds called chlorides. Group 14 elements react with chlorine by donating electrons to the chlorine atoms, creating stable chloro compounds.
Each Group 14 element reacts differently with chlorine. The balanced chemical reactions highlight this interaction:

• Carbon reacts to form carbon tetrachloride: \( \mathrm{C} + 2\mathrm{Cl}_2 \rightarrow \mathrm{CCl}_4 \).
• Silicon forms silicon tetrachloride: \( \mathrm{Si} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SiCl}_4 \).
• Germanium produces germanium tetrachloride: \( \mathrm{Ge} + 2\mathrm{Cl}_2 \rightarrow \mathrm{GeCl}_4 \).
• Tin can either form tin dichloride: \( \mathrm{Sn} + \mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_2 \) or tin tetrachloride: \( \mathrm{Sn} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_4 \).

These reactions illustrate the ability of chlorine to attract and stabilize additional electrons from other elements, leading each element to form its respective chloride product efficiently.

Covalent Bonding

Covalent bonding happens when atoms share one or more pairs of electrons. This form of bonding generally occurs between non-metals that have similar electronegativities. In the context of Group 14 elements reacting with chlorine, covalent bonding is a common result.
The products of these reactions such as carbon tetrachloride \( \mathrm{CCl}_4 \), silicon tetrachloride \( \mathrm{SiCl}_4 \), and germanium tetrachloride \( \mathrm{GeCl}_4 \) all involve covalent bonds. This means that carbon, silicon, and germanium are sharing their valence electrons with chlorine atoms to achieve stable electronic configurations.

• These compounds typically have strong intermolecular forces due to the shared electrons, resulting in relatively high melting and boiling points.
• The covalent nature ensures that the compounds are more stable than if the bonds were purely ionic.

In the case of tin compounds, \( \mathrm{SnCl}_2 \) and \( \mathrm{SnCl}_4 \), the bonds may show some degree of ionic character due to the metallic property of tin, although they predominantly involve covalent interactions due to sharing electrons.

Balanced Equations

A balanced equation in chemistry ensures that the number of atoms for each element is equal on both sides of the equation. This reflects the law of conservation of mass, which states that mass in a closed system must remain constant over time.
When Group 14 elements react with chlorine, the balanced chemical equations are essential to understand the stoichiometry of the reactions. Here's how these equations are balanced:

• For carbon: \( \mathrm{C} + 2\mathrm{Cl}_2 \rightarrow \mathrm{CCl}_4 \), two \( \mathrm{Cl}_2 \) molecules are needed for each carbon atom to form carbon tetrachloride.
• Silicon requires the same stoichiometry: \( \mathrm{Si} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SiCl}_4 \).
• Germanium also follows suit with a similar equation: \( \mathrm{Ge} + 2\mathrm{Cl}_2 \rightarrow \mathrm{GeCl}_4 \).
• For tin, we can have either \( \mathrm{Sn} + \mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_2 \) indicating partial reactivity or \( \mathrm{Sn} + 2\mathrm{Cl}_2 \rightarrow \mathrm{SnCl}_4 \) showing full reaction potential.

By accurately balancing these equations, we effectively convey the chemical changes happening in the reactions, enabling a deeper understanding of the participant atoms and molecules.