Chemical Bonding and Molecular Formulas Explained

Chemical Bonding: Principles and Types

Chemical bonding refers to the forces acting between two atoms that keep them together to form stable chemical species.

Covalent Bonds

Formed between non-metal atoms that attract electrons to complete their octet. Atoms share electrons because neither tends to yield them.

Characteristics:

• Low melting and boiling points due to weak intermolecular forces.
• Poor conductors of electricity as electrons are fixed within the molecule.
• Soluble in nonpolar solvents such as CCl₄, CS₂, or C₆H₆.

Ionic Bonds

Formed between metals (M) and non-metals (NM). The metal tends to donate electrons, while the non-metal captures them, resulting in electron transfer.

Characteristics:

• High melting and boiling points due to strong electrostatic forces.
• Hard materials requiring significant energy to break.
• Brittle: shifting the crystal lattice causes ion-ion repulsion, leading to fracture.
• Non-conductors of electricity in solid form; generally soluble in polar solvents like water.

Metallic Bonds

Characteristics:

• Good conductors of electricity due to the mobility of electrons within the crystal lattice.
• Ductile and malleable because there is no electrostatic repulsion between cations.
• Metallic sheen; usually white or silver in appearance.
• Variable melting and boiling points.

Chemical Formulas and Molecular Representation

A chemical formula is a representation of a compound indicating the elements present and their proportions.

• Empirical Formula: Indicates the simplest relative proportions of atoms in a compound.
• Molecular Formula: Indicates the actual number of atoms constituting the molecule.
• Structural Formula: Indicates the links between carbon atoms.
• Developed Formula: Shows all bonds between every atom in the molecule.
• Space-Filling Formula: Represents the spatial direction of chemical bonds.

Functional Groups

A functional group is an atom or group of atoms that bind in a characteristic manner, determining the chemical properties of the compound.

Isomers

Isomers are two or more compounds sharing the same molecular formula but possessing different developed or spatial structures, resulting in unique properties.

Types of Isomerism:

• Structural (Flat): Chain, position, and functional isomers.
• Stereoisomerism (Spatial): Conformational, configurational, and optical isomers.