Is the atomic weight of cobalt 58.9?
The correct answer and explanation is:
Yes, the atomic weight of cobalt is approximately 58.93 u (atomic mass units). This value is the weighted average mass of the naturally occurring isotopes of cobalt.
Cobalt has two primary isotopes, Co-59 and Co-58. Co-59 is stable and abundant, making up about 100% of natural cobalt. The atomic mass of Co-59 is about 58.9332 u, which is why the atomic weight of cobalt is nearly 59.
The atomic weight of an element is determined by considering the isotopic masses of its naturally occurring isotopes and their relative abundances. In the case of cobalt, although Co-58 exists, it is much less abundant than Co-59. The slight difference in mass between these isotopes does not significantly affect the overall atomic weight, which is why the atomic weight of cobalt is listed as approximately 58.93.
In practice, atomic weight is a useful concept in chemistry because it represents the average mass of atoms in a naturally occurring sample of an element. This is the value commonly used in calculations involving moles, molar mass, and stoichiometry in chemical reactions. When working with cobalt in chemical reactions, its atomic weight of 58.93 g/mol is used to calculate molar quantities, which helps chemists determine how much cobalt is needed or produced in various reactions.
While cobalt’s atomic weight is a precise value based on current measurements, it can be subject to slight changes as more accurate measurements of isotopic abundances and masses become available. However, 58.93 is generally accepted as the atomic weight for most practical purposes.