Carbon's unique ability to form stable, strong covalent bonds with other carbon atoms allows it to create long, complex chains and rings, a property known as catenation, which is fundamental to organic chemistry.

A metallic bond is characterized by the electrostatic attraction between a lattice of positively charged metal ions (cations) and a 'sea' of delocalized valence electrons. This electrostatic interaction is responsible for the unique properties of metals, such as high electrical and thermal conductivity.

A cation is a positively charged ion formed when an atom loses one or more electrons. Conversely, an anion is a negatively charged ion formed when an atom gains one or more electrons to achieve a stable electronic configuration.

Common salt, also known as sodium chloride, is an ionic compound composed of sodium cations (Na+) and chloride anions (Cl-) in a 1:1 ratio. Its chemical formula is represented as NaCl.

Ionic bonds result from the complete transfer of electrons from a metal to a non-metal, creating electrostatic attraction. Covalent bonds result from the mutual sharing of electron pairs between non-metal atoms to achieve stability.

To determine the chemical formula of an ionic compound, the total positive charge must balance the total negative charge. With aluminum having a +3 charge and oxygen having a -2 charge, the criss-cross method indicates that two aluminum ions (+6 total) are required to balance three oxide ions (-6 total), resulting in Al2O3.

Methane consists of a central carbon atom bonded to four hydrogen atoms. Each C-H bond is formed by the sharing of one electron from carbon and one from hydrogen, resulting in four single covalent bonds. The molecule adopts a tetrahedral geometry to minimize electron pair repulsion.

Ionic solids are characterized by a rigid crystal lattice structure, making them hard and brittle. The strong electrostatic attractions result in high melting points. When melted or dissolved in water, the ions become mobile, allowing the substance to conduct electricity effectively.

The formula Al2(SO4)3 consists of two aluminum ions (Al3+) and three sulfate polyatomic ions (SO4^2-). According to IUPAC nomenclature rules for ionic compounds, the cation is named first followed by the anion. Therefore, the name is aluminum sulfate. Sulfite would be SO3^2-, and sulfide would be S^2-, making those options incorrect.

Covalent compounds consist of neutral molecules held together by shared electron pairs. Because they lack the charged ions necessary to interact strongly with the polar water molecules, they are generally insoluble in water, following the 'like dissolves like' principle.