In class 11, the atomic mass of elements is typically taught to two decimal places of precision. This level of precision is sufficient for most introductory chemistry courses and provides a good understanding of the relative atomic masses of elements.
The atomic mass of an element is typically listed on the periodic table, and it represents the average mass of all the naturally occurring isotopes of that element. The two decimal places allow for distinguishing between different elements and understanding their relative masses.
For example, the atomic mass of carbon is commonly listed as 12.01 on the periodic table. This indicates that the average atomic mass of carbon, considering its isotopes, is approximately 12.01 atomic mass units (amu).
It's worth noting that in advanced chemistry studies or more specialized areas, greater precision may be required, and atomic masses can be given to more decimal places. However, for the purposes of class 11 chemistry, two decimal places should be sufficient for understanding and calculations involving atomic masses.