Question

If electrones exist in a atoms then why electrons are not taken for atomic mass calculations

Answer 1

Answer:

Electrons are present in atoms, but they are not taken into atomic mass calculations as it's mass very negligible and compared to others.

The other taken into considerations is also that electron no on an atom changes continuosly in an atom according to it's surroundings. If electrons is taken into consideration then when an atom cimes to atable octate state the mass will also change, but this not happens.

Here Mass of an elctron, proton and neutron are given here for your comparisions :-

Mass of an electron : 9.10938356 × 10-31 kilograms

Mass of a proton : 1.672623 x 10-27 kg

Mass of an Neutron : 1.674929 x 10-27 kg