Final answer:
The term for the number of atoms bonded to a central atom in a molecule or lattice is the coordination number, which is key in understanding the molecular structure and is often used when describing lattices or complexes.
Step-by-step explanation:
The number that represents the number of atoms that will bond to the central atom in a molecule or lattice is known as the coordination number. The coordination number can refer to either the number of coordinate covalent bonds to the central metal atom in a complex or the number of closest contacts to an atom in a crystalline form. It is an integral part of understanding the coordination sphere, which includes the central metal atom or ion and its attached ligands. In chemical formulas, the coordination sphere is denoted by brackets and can vary depending on the metal ion and the ligands present. For instance, the coordination number of a silver ion in [Ag(NH3)2] is two because it is bonded to two ammonia molecules (NH3), and in a molecule like AB4, a central atom A is surrounded by four B atoms making the coordination number four.