Why aren't the properties of sodium chloride the same as the elements that compose it?
The easiest answer is that there has been a chemical change and the properties of the products are not the same as the reactants.
One atom of the element Na has lost an electron to become a sodium ion (a cation) and one atom of the element Cl has gained an electron to become a chloride ion (an anion). The properties are not the same because a chemical reaction has taken place.
Oh I see, thank you!
The properties of sodium chloride, also known as table salt, are different from the properties of its individual elements, sodium and chlorine, due to a phenomenon known as chemical bonding.
Sodium is a highly reactive metal that reacts vigorously with water and air. It readily loses its outermost electron to achieve a stable electron configuration, forming a positively charged ion called a cation. On the other hand, chlorine is a highly reactive non-metal that tends to gain one electron to achieve a stable electron configuration, forming a negatively charged ion called an anion.
When sodium and chlorine react, sodium transfers its single outer electron to chlorine, forming sodium ions (Na+) and chloride ions (Cl-). These oppositely charged ions are attracted to each other by strong electrostatic forces, creating an ionic bond. This bond is responsible for holding the sodium and chloride ions together in a crystal lattice structure, resulting in the formation of sodium chloride.
The ionic bond in sodium chloride is characterized by a strong force of attraction between the positive and negative ions, which creates a three-dimensional array of alternating sodium and chloride ions. This arrangement leads to several unique properties of sodium chloride, such as:
1. High Melting and Boiling Point: Sodium chloride has a high melting point of 801 degrees Celsius and a high boiling point of 1413 degrees Celsius. This is due to the strong ionic bonds that must be broken in order to change the state of the substance.
2. Solubility in Water: Sodium chloride is highly soluble in water due to its ionic nature. The polar water molecules surround the positively charged sodium ions and negatively charged chloride ions, causing them to dissociate and spread throughout the solution.
3. Electrical Conductivity: When dissolved in water or melted, sodium chloride can conduct electricity due to the presence of mobile ions. The ions can move freely and carry an electric charge, allowing the substance to conduct electricity.
In summary, the properties of sodium chloride differ from the properties of sodium and chlorine because the compound has a different chemical composition and is governed by the strong ionic bond formed between oppositely charged ions.