Explain why ionic solids like \(\mathrm{NaCl}\) have high melting points yet dissolve readily in water, whereas network solids like diamond have very high melting points and do not dissolve.

Ionic bonds form when atoms with significantly different electronegativities transfer electrons, creating positively charged cations and negatively charged anions. These ions have a strong electrostatic attraction to one another, effectively holding them together in a lattice structure, commonly seen in salts like sodium chloride (NaCl). This bond's strength is mainly due to the large charge difference between the ions, which significantly influences both the physical properties and the chemical behavior of the resultant ionic compounds.

For example, when sodium (Na), a metal, reacts with chlorine (Cl), a non-metal, the sodium atom donates an electron to the chlorine atom, resulting in a sodium cation (Na⁺) and a chloride anion (Cl⁻). This transfer of electrons and the subsequent electrostatic attraction between the oppositely charged ions is the foundation of ionic bonding.

The high melting points of ionic solids, such as NaCl, can be attributed to the strong electrostatic forces holding the ions in place within their crystalline lattice. In order to melt an ionic solid, a significant amount of energy is required to overcome these forces. This energy disrupts the orderly arrangement of ions, allowing them to move freely about in a liquid state.

The lattice structure, with its repeating pattern of cations and anions, is so stable and energetically favorable that only high temperatures can provide the energy necessary to break apart these ionic bonds. Thus, substances with ionic bonds typically exhibit high melting points, a reflection of the bond's strength and the solid's structural rigidity.

Ion-dipole interactions occur when a polar molecule, like water, surrounds an ion. The polar molecule has regions with partial positive and negative charges, which are attracted to the oppositely charged ions. This kind of interaction is especially potent in solvation processes, where the solvent molecules work to separate individual ions from the bulk solid and stabilize them in solution.

In the context of solubility, when NaCl is placed in water, water molecules, with their partially negative oxygen and partially positive hydrogens, orient themselves around the Na⁺ and Cl⁻ ions. The degree to which these ion-dipole forces can overcome the ionic bonds within NaCl dictates how readily the ionic solid will dissolve in water. This efficient dissolution is why many ionic compounds, despite their high melting points, can be dissolved in polar solvents like water.

Network solids, such as diamond, consist of atoms connected by a continuous network of covalent bonds. These solids are characterized by their extreme hardness and very high melting points. The covalent bonds within a network solid are not localized between two atoms but extend throughout the entire structure, creating a robust three-dimensional matrix.

In diamonds, each carbon atom is tetrahedrally bonded to four other carbon atoms, resulting in a very stable and rigid lattice. The strength and durability of the covalent bonds throughout the entire crystal make network solids incredibly resistant to high temperatures and pressures, accounting for their exceptionally high melting points.

The solubility of a substance in water depends on the substance's ability to interact with water molecules. While ionic compounds tend to be soluble because they can form favorable ion-dipole interactions with water, network solids do not. The robust covalent bonds in network solids are too strong to be disrupted by the relatively weaker interactions with water molecules.

Solubility can also be explained by the 'like dissolves like' principle, whereby polar or ionic substances tend to dissolve in polar solvents, and nonpolar substances tend to dissolve in nonpolar solvents. Due to their polar nature, the ionic solids are generally soluble in water, a polar solvent, whereas network solids are not because they do not have separable polar units capable of interacting with the water.

Covalent bonds are formed when two or more atoms share electrons, leading to the creation of a molecule. The shared electrons allow each atom in the molecule to achieve a stable electron configuration, typically resembling that of the nearest noble gas. These bonds can be single, double, or triple, depending on the number of shared electron pairs.

Covalent bonding is the key characteristic of a vast array of substances, ranging from simple molecules like O₂ to complex proteins and DNA. In network solids like diamond or quartz, the extensive covalent bonding leads to their remarkable properties, such as exceptional strength and high melting points. These continuous networks of covalent bonds showcase the bond's versatility and strength in creating a multitude of substances with varying chemical and physical properties.