Problem 37 - Chemistry Matter and Change

Question

State the name and formula for the compound formed from Mg and Cl.

Step-by-Step Solution

Answer

The compound is Magnesium Chloride with the formula \( \text{MgCl}_2 \).

Step 1: Identify the Elements

First, we need to identify the elements involved in forming the compound. The elements given are Magnesium (Mg) and Chlorine (Cl). Magnesium is an alkaline earth metal, while chlorine is a halogen.

Step 2: Determine the Charges of Ions

Magnesium typically forms a cation with a charge of +2, denoted as \( \text{Mg}^{2+} \). Chlorine typically forms an anion with a charge of -1, denoted as \( \text{Cl}^{-} \).

Step 3: Balance the Charges

To balance the charges between the ions so the net charge of the compound is zero, we use one \( \text{Mg}^{2+} \) ion and two \( \text{Cl}^{-} \) ions. This gives a total of +2 from magnesium and -2 from two chloride ions, which balances out to zero.

Step 4: Write the Formula

With the charges balanced, we can determine the chemical formula of the compound. The formula consists of one magnesium ion and two chloride ions, written as \( \text{MgCl}_2 \).

Step 5: State the Name of the Compound

The compound formed is named based on its elements. Since it consists of magnesium and chlorine, it is called Magnesium Chloride.

Key Concepts

Magnesium Chloride

Magnesium chloride is a commonly known chemical compound formed when magnesium and chlorine elements combine. Magnesium, symbolized as \( \text{Mg} \), is a metal found in the alkaline earth metals group on the periodic table. Chlorine, with the symbol \( \text{Cl} \), belongs to the halogens, which are non-metals. When these two elements come together, they form a salt-like substance called magnesium chloride. This compound is used in various applications, such as de-icing roads or in magnesium supplement formulations. Understanding the formation of magnesium chloride helps us learn about how different types of chemical compounds are named and how they maintain stability by balancing charges.

Ionic Bonding

Ionic bonding is a type of chemical bonding where atoms transfer electrons to achieve a full outer shell, thus becoming ions. In the case of magnesium chloride, an ionic bond forms between magnesium and chlorine atoms. Magnesium, a metal, tends to lose electrons easily and become a positively charged cation \( (\text{Mg}^{2+}) \), due to its position in the periodic table. Chlorine, a non-metal, readily gains an electron to become a negatively charged anion \( (\text{Cl}^{-}) \). This transfer creates ions with opposite charges that attract each other, resulting in a strong ionic bond that holds the elements together.

• Metals like magnesium usually form cations.
• Non-metals like chlorine form anions.
• Ionic bonding results in stable compounds with neutral electrical charges.

Chemical Formula

A chemical formula represents the proportions of atoms in a compound and provides the means to convey the structure of a molecule using element symbols and numbers. The chemical formula for magnesium chloride is \( \text{MgCl}_2 \). This formula indicates that the compound is formed by one magnesium atom and two chlorine atoms.

• The subscript '2' after \( \text{Cl} \) shows there are two chloride ions needed for every magnesium ion.
• Knowledge of ion charges helps in determining the correct formula for the compound.

This notation simplifies complex molecular structures, making it easier to understand chemical reactions and properties of substances.

Ion Charge Balancing

Ion charge balancing is a crucial process in forming stable ionic compounds, ensuring the overall electrical neutrality. When a metal like magnesium (\( \text{Mg}^{2+} \)) and a non-metal like chlorine (\( \text{Cl}^{-} \)) combine, their charges must cancel out to form a neutral compound. To balance the charges in magnesium chloride, one \( \text{Mg}^{2+} \) cation requires two \( \text{Cl}^{-} \) anions to offset the +2 charge of magnesium with the total -2 from two chloride ions. This results in a stable compound with a neutral charge, \( \text{MgCl}_2 \), indicating perfectly balanced ion charges.

• The fundamental goal is to achieve an overall neutral charge.
• Understanding charge balancing is key to writing correct chemical formulas.