A compound of gallium with chlorine has a melting point of 77°C and a boiling point of 201°C. Is the compound ionic or covalent? What is a likely formula?

Verified step by step guidance

1. Identify the type of bonding based on the properties of the compound. Ionic compounds typically have high melting and boiling points, while covalent compounds tend to have lower melting and boiling points. Since the melting point (77°C) and boiling point (201°C) are relatively low, this suggests the compound is likely covalent.
2. Consider the elements involved. Gallium (Ga) is a metal, and chlorine (Cl) is a nonmetal. Compounds between metals and nonmetals are often ionic, but exceptions exist, especially when the metal is less electropositive, as is the case with gallium.
3. Determine the likely formula by considering the valence of gallium and chlorine. Gallium typically forms a +3 charge (Ga³⁺), and chlorine typically forms a -1 charge (Cl⁻). To balance the charges, three chlorine atoms are needed for every gallium atom, resulting in the formula GaCl₃.
4. Verify the formula by checking the total charges. One Ga³⁺ ion contributes +3, and three Cl⁻ ions contribute -3. The charges balance to zero, confirming the formula GaCl₃ is correct.
5. Conclude that the compound is likely covalent based on its physical properties and the nature of the bonding in GaCl₃, which involves sharing of electrons rather than complete transfer, as gallium is not highly electropositive.

Key Concepts

Ionic vs. Covalent Compounds

Ionic compounds are formed when electrons are transferred from one atom to another, resulting in charged ions that attract each other. They typically have high melting and boiling points due to strong electrostatic forces. In contrast, covalent compounds involve the sharing of electrons between atoms, leading to lower melting and boiling points. Understanding these differences is crucial for determining the nature of the compound in question.

Melting and Boiling Points

The melting point is the temperature at which a solid becomes a liquid, while the boiling point is the temperature at which a liquid becomes a gas. High melting and boiling points often indicate strong intermolecular forces, which are characteristic of ionic compounds. In this case, the compound's melting point of 77°C and boiling point of 201°C suggest significant intermolecular interactions, which can help identify its nature.

Chemical Formulas

A chemical formula represents the elements in a compound and their respective ratios. For ionic compounds, the formula is typically derived from the charges of the ions involved. In the case of gallium and chlorine, gallium typically forms a +3 ion, while chlorine forms a -1 ion, leading to a likely formula of GaCl3. Understanding how to derive chemical formulas is essential for predicting the composition of the compound.