In \(\left[\mathrm{Ag}(\mathrm{CN})_{2}\right]^{2-}\), the number of \(\pi\) bonds is: (a) 2 (b) 3 (c) 4 (d) 6

Chemical bonding is a core concept in chemistry that describes the force that holds atoms together in molecules and compounds. Atoms can form bonds in different ways, primarily through ionic, covalent, metallic, and hydrogen bonding.

Within covalent bonding, there are two main types of bonds—sigma ( ) and pi () bonds. Sigma () bonds are the first bonds formed between two atoms, characterized by the head-on overlapping of orbitals. In contrast, pi () bonds are formed when parallel orbitals overlap and electrons are shared in two regions above and below the bonding axis, rather than directly between the nuclei.

) bonds are stronger and more stable than bonds because the overlap is greater along the axis connecting the two nuclei. However, ) bonds contribute to the molecule's ability to absorb light and participate in specific reactions.

Coordination chemistry involves the study of compounds with a central metal atom or ion, known as a coordination center, surrounded by molecules or anions called ligands. These ligands donate electron pairs to the metal to form coordination bonds.

The nature of ligands can significantly influence the properties of the coordination complex including its color, magnetic behavior, and reactivity. In the given example of [Ag(CN)_{2}]^{2-}, cyanide ions act as ligands forming a coordination compound with the silver ion. The cyanide ion, being a strong lig-and, firmly holds the silver ion, creating a stable complex ion with interesting chemical properties.

Molecular structure refers to the three-dimensional arrangement of atoms within a molecule. Understanding the molecular structure is crucial for predicting the physical and chemical properties of a molecule.

For example, the linear structure of the cyanide ion (CN-) in the [Ag(CN)_{2}]^{2-} complex determines how it will interact with the silver ion. The molecular geometry around the silver ion is influenced by the number and spatial arrangement of the cyanide ligands, helping to define the overall shape, bond angles, and potential for isomerism within the complex. Molecular structure can be predicted using theories such as VSEPR (Valence Shell Electron Pair Repulsion), which is pivotal in understanding the geometry of coordination complexes.