Question

while considering the mass of an atom , The mass of electron in not considered Why?​

Answer 1

Explanation:

When considering atomic mass, it is customary to ignore the mass of any electrons and calculate the atom's mass based on the number of protons and neutrons alone. Electrons contribute greatly to the atom's charge, as each electron has a negative charge equal to the positive charge of a proton.

Answer 2

Answer:

Electrons are extremely small. The mass of an electron is only about 1/2000 the mass of a proton or neutron, so electrons contribute virtually nothing to the total mass of an atom. Electrons have an electric charge of −1, which is equal but opposite to the charge of a proton, which is +1