Selected chlorides have the following melting points: NaCl (801 °C), MgCl2 (714 °C), PCl3 (-94 °C), SCl2 (-121 °C) (a) For each compound, indicate what type its solid form is (molecular, metallic, ionic, or covalent-network).

Key Concepts

Ionic Compounds

Ionic compounds are formed from the electrostatic attraction between positively and negatively charged ions. They typically consist of a metal and a non-metal, resulting in a crystalline structure that exhibits high melting points due to strong ionic bonds. Examples include NaCl and MgCl2, which are solid at room temperature and have high melting points.

Molecular Compounds

Molecular compounds are formed when two or more non-metals share electrons through covalent bonds. These compounds usually have lower melting and boiling points compared to ionic compounds and can exist as gases, liquids, or solids at room temperature. PCl3 and SCl2 are examples of molecular compounds, characterized by their discrete molecular units.

Melting Points and Bonding Types

The melting point of a substance is influenced by the type of bonding present. Ionic compounds generally have high melting points due to the strong forces between ions, while molecular compounds have lower melting points due to weaker van der Waals forces. Understanding the relationship between bonding types and melting points helps in classifying compounds accurately.