Chemical bonding and structure is a fundamental topic in IB Chemistry that investigates the forces that bind atoms and molecules together. Understanding chemical bonding is crucial to understanding the properties and behaviors of matter, including reactions that take place in our daily lives. In this blog post, we will discuss the different types of chemical bonding, ionic and covalent compounds’ properties, and molecular geometries of various compounds.
Types of Chemical Bonding
There are three main types of chemical bonding which include; ionic bonding, covalent bond and metallic bonding. Ionic bonding takes place between a metal and nonmetal where metal donates electrons to nonmetal forming a cation and anion. Covalent bonding happens between nonmetals where atoms share electrons to form a molecule. Metallic bonding occurs among metals whereby the valence electrons are shared among all atoms in a metal lattice.
Example:
The bonding in sodium chloride (NaCl) is ionic, where sodium (Na) donates an electron to chlorine (Cl) to form a cation (Na+) and an anion (Cl-).
Properties of ionic compounds Ionic compounds have high melting and boiling points due to the strong electrostatic forces between the oppositely charged ions. They are also brittle and conduct electricity when molten or in solution.
Example:
Sodium chloride has a high melting point of 801°C due to the strong ionic bonds between sodium and chloride ions.
Characteristics of Ionic Compounds Because of the strong electromagnetic forces between ions of opposite charges, ionic compounds have high melting and boiling points They are also brittle and conduct electricity when molten or in solution.
Example:
Water (H2O) is a polar covalent compound because the difference in electronegativity between oxygen and hydrogen creates a partial negative charge on the oxygen atom and a partial positive charge on the hydrogen atom
Molecular geometries The shape and polarity of a molecule are determined by the arrangement of its atoms. Molecular geometries can be predicted using the VSEPR (valence shell electron pair repulsion) theory, which states that the electron pairs around a central atom repel each other and adopt a geometry that minimizes their repulsion.
Example:
Methane (CH4) has a tetrahedral molecular geometry due to the repulsion between its four electron pairs.
Chemical bonding and structure is an important topic in IB chemistry that helps us understand the properties and behavior of substances. By understanding the types of chemical bonds, the properties of ionic covalent compounds, and the molecular geometry of compounds, we can better understand the world around us
