The mass of an electron is not directly calculated from the atomic weight and charge of an atom. The electron mass is a fundamental constant of nature and is not dependent on the specific atom or its charge.
The exact value of the electron mass is approximately 9.10938356 x 10^-31 kilograms (kg) or 0.00054858 atomic mass units (u). This value is obtained through experimental measurements and is known with high precision.
In atomic systems, the atomic weight (also known as the atomic mass) represents the average mass of all the isotopes of an element, taking into account their relative abundances. The atomic weight is expressed in atomic mass units (u) and is typically listed on the periodic table.
The charge of an electron is a fundamental property of the electron and is equal to -1 elementary charge, which is approximately -1.602176634 x 10^-19 coulombs (C).
It's important to note that the electron mass, atomic weight, and electron charge are distinct quantities, and their values are not interrelated by a direct calculation.