Question

(a) Use Lewis symbols to represent the reaction that occurs between Ca and F atoms. (b) What is the chemical formula of the most likely product? (c) How many electrons are transferred? ( \(\mathbf{d} )\) Which atom loses electrons in the reaction?

Short answer

(a) The reaction between Ca and F using Lewis symbols is represented as: \[ \underset{\displaystyle .}{\text{Ca}} + 2 \underset{\displaystyle :.}{\text{F}} \rightarrow \text{Ca}^{2+} + 2 \text{F}^{-} \] (b) The chemical formula of the most likely product is CaF2. (c) A total of 2 electrons are transferred during the reaction. (d) The Calcium atom (Ca) loses electrons in the reaction.

Step-by-step solution

Determine the Lewis symbols for Ca and F

First, let's determine the Lewis symbols for calcium (Ca) and fluorine (F) atoms. The Lewis symbol of an atom represents its valence electrons as dots surrounding the chemical symbol. Calcium has 2 valence electrons and fluorine has 7 valence electrons. \[ \text{Ca:} \: \: \: \underset{\displaystyle .}{\text{Ca}} \] \[ \text{F:} \: \: \: \underset{\displaystyle :.}{\text{F}} \]

Determine the reaction between Ca and F using Lewis symbols

Calcium has 2 valence electrons that can be lost to achieve a stable noble gas configuration, and fluorine needs 1 more electron to achieve a stable noble gas configuration. Therefore, one calcium atom can react with two fluorine atoms to form an ionic compound. In this reaction, calcium loses 2 electrons, and each fluorine atom gains 1 electron. Here's the representation of the reaction using Lewis symbols (the arrows indicate electron transfer): \[ \underset{\displaystyle .}{\text{Ca}} + 2 \underset{\displaystyle :.}{\text{F}} \rightarrow \text{Ca}^{2+} + 2 \text{F}^{-} \] #a)# The representation of the reaction using Lewis symbols is shown above.

Determine the chemical formula of the product

The product of this reaction is an ionic compound formed between calcium ion (Ca²⁺) and two fluoride ions (2F⁻). The chemical formula of the product is: \( \text{CaF}_2 \) #b)# The chemical formula of the most likely product is CaF₂.

Determine the number of electrons transferred

One calcium atom loses 2 electrons, and each of the two fluorine atoms gains 1 electron. Therefore, a total of 2 electrons are transferred during the reaction. #c)# 2 electrons are transferred in the reaction.

Identify which atom loses electrons

In this reaction, the calcium atom loses 2 electrons to form the Ca²⁺ ion. #d)# Calcium (Ca) loses electrons in the reaction.

Key concepts

Chemical Bonding

Understanding chemical bonding is fundamental to performing any chemical reaction. Bonds are the connections between atoms that allow the formation of chemical substances that contain two or more atoms. The type of bond mainly depends on the elements involved and their electron configurations.

There are three primary types of chemical bonding:

• Covalent bonding where atoms share electrons.
• Ionic bonding which involves the transfer of electrons from one atom to another.
• Metallic bonding found in metals, where electrons are free to move around.

In our exercise, the focus is on ionic bonding, which occurs when a metal (in this case, calcium) gives up electrons to a non-metal (fluorine), resulting in positively and negatively charged ions that attract each other. This attraction forms the ionic bond and the resulting ionic compound, CaF₂.

Ionic Compounds

Ionic compounds are substances composed of ions bound together by electrostatic forces termed ionic bonding. An ion is an atom or molecule that has lost or gained one or more electrons, giving it a net positive or negative charge. Ionic compounds typically form between metals and nonmetals, where metals tend to lose electrons and nonmetals tend to gain electrons.

Characteristics of ionic compounds include:

• High melting and boiling points due to the strong attraction between cations and anions.
• Electrical conductivity when dissolved in water or melted, as ions are free to move.
• Brittle nature, as any displacement of ions can disrupt the crystal lattice, causing the material to break.

The product of the chemical reaction in our example is calcium fluoride, CaF₂, an ionic compound where a calcium atom has transferred its two electrons to two fluorine atoms, achieving stable electron configurations for both.

Electron Transfer

Electron transfer is the process of moving electrons from one atom to another during a chemical reaction, transforming the oxidation state of the atoms. This transfer is fundamental in the formation of ionic bonds.

In the given exercise, we've observed that:

• Calcium (Ca), a metal, is willing to give up its two valence electrons to achieve a noble gas electron configuration.
• Fluorine (F), a non-metal, is eager to accept one electron to complete its valence shell to also reach a noble gas electron configuration.

With the transfer of two electrons from calcium to the two fluorine atoms:

• Calcium becomes a cation, Ca²⁺.
• Each fluorine atom becomes an anion, F^-.

Thus establishing a classic ionic bond through electron transfer. In terms of the number of electrons transferred in our example, a total of two electrons were moved from calcium to the two fluorine atoms—configuring the formula CaF₂ for calcium fluoride.